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Abstract:

Methods for preparing solvent-dry, stackable tailings. The method can
include the steps of adding a first quantity of first solvent to a
bitumen material to form a first mixture, separating a first quantity of
bitumen-enriched solvent from the first mixture and thereby creating
first solvent-wet tailings, adding a quantity of second solvent to first
solvent-wet tailings to separate a first quantity of first solvent
component from the first solvent-wet tailings and thereby producing
second solvent-wet tailings, and adding a quantity of water to the second
solvent-wet tailings to separate a first quantity of second solvent
component from the second solvent-wet tailings and thereby forming
solvent-dry, stackable tailings.

Claims:

1. A method comprising: passing a first solvent through a first quantity
of bituminous material; passing a second solvent through the first
quantity of bituminous material; and passing water through the first
quantity of bituminous material; wherein the second solvent comprises a
paraffinic solvent.

2. The method as recited in claim 1, further comprising: loading the
first quantity of bituminous material into a sealed vessel prior to
passing the first solvent, the second solvent, and the water through the
first quantity of bituminous material.

3. The method as recited in claim 2, wherein the sealed vessel is a
sealed vertical column having a top end and a bottom end opposite the top
end.

4. The method as recited in claim 3, wherein passing the first solvent
through the first quantity of bituminous material comprises: adding the
first solvent at the top end of the sealed vertical column; introducing
inert gas into the sealed vertical column at the top end of the sealed
vertical column and pushing the first solvent down through the bituminous
material loaded in the sealed vertical column; and collecting the first
solvent exiting the bottom end of the sealed vertical column.

5. The method as recited in claim 3, wherein the first solvent exiting
the bottom end of the vertical column comprises first solvent and
bitumen.

6. The method as recited in claim 2, wherein passing the second solvent
through the first quantity of bituminous material comprises: adding the
second solvent at the top end of the vertical column; introducing inert
gas into the vertical column at the top end of the vertical column and
pushing the second solvent down through the bituminous material loaded in
the vertical column; and collecting the second solvent exiting the bottom
end of the vertical column.

7. The method as recited in claim 6, wherein the second solvent exiting
the bottom end of the vertical column comprises second solvent and first
solvent.

8. The method as recited in claim 7, wherein the second solvent exiting
the bottom end of the vertical column further comprises bitumen.

9. The method as recited in claim 2, wherein passing the water through
the first quantity of bituminous material comprises: adding the water at
a top end of the vertical column; introducing inert gas into the vertical
column at the top end of the vertical column and pushing the water down
through the bituminous material loaded in the vertical column; and
collecting residual second solvent exiting the bottom end of the vertical
column.

11. The method as recited in claim 1, wherein the bituminous material is
solvent-wet.

12. The method as recited in claim 2, wherein the bituminous material
loaded in the vertical column comprises a plurality of interstitial
pores, and wherein the ratio of volume of water passed through the first
quantity of bituminous to total volume of the plurality of interstitial
pores is from 1:1 to 5:1.

13. The method as recited in claim 2, further comprising: removing the
first quantity of bituminous material from the sealed vessel after
passing the water through the first quantity of bituminous material.

14. The method as recited in claim 13, wherein the bituminous material
removed from the sealed vessel comprises less than 200 ppm on a weight
basis of first solvent, less than 100 ppm on a weight basis of second
solvent, and less than 2% by weight bitumen.

15. A method comprising: mixing first solvent with bituminous material
and forming a mixture; separating the mixture into a bitumen-enriched
solvent phase and a bitumen-depleted tailings phase; passing second
solvent through the bitumen-depleted tailings phase; passing third
solvent through the bitumen-depleted tailings phase; and passing water
through the bitumen-depleted tailings phase; wherein the third solvent
comprises paraffinic solvent.

16. The method as recited in claim 15, wherein the first solvent is the
same solvent as the second solvent and the first solvent is an aromatic
solvent.

17. A method comprising: providing a bituminous material comprising a
paraffinic solvent; passing water through the bituminous material and
pushing paraffinic solvent out of the bituminous material; and collecting
paraffinic solvent pushed out of the bituminous material.

19. A method comprising: contacting a bituminous material with a first
solvent and forming first solvent-wet bituminous material; contacting the
first solvent-wet bituminous material with a second solvent and forming
second solvent-wet bituminous material; and contacting the second
solvent-wet bituminous material with water and forming a water-wet
bituminous material; wherein the second solvent comprises a paraffinic
solvent.

20. The method as recited in claim 19, wherein contacting the bituminous
material with the first solvent comprises: mixing the bituminous material
with the first solvent and forming the first solvent-wet bituminous
material; and separating a bitumen-enriched first solvent phase from the
first solvent-wet bituminous material using a hydrocyclone.

21. The method as recited in claim 19, wherein contacting the first
solvent-wet bituminous material with the second solvent comprises: mixing
the first solvent-wet bituminous material with the second solvent and
forming the second solvent-wet bituminous material; and separating a
mixture of first solvent and second solvent from the second solvent-wet
bituminous material using a hydrocyclone.

22. The method as recited in claim 19, wherein contacting the second
solvent-wet bituminous material with the water comprises: mixing the
second solvent-wet bituminous material with water and forming the
water-wet bituminous material; and separating a mixture of second solvent
and water from the water-wet bituminous material using a hydrocyclone.

Description:

[0001] This application is a Continuation-In-Part application of U.S.
application Ser. No. 12/692,127, filed Jan. 22, 2010, and herein
incorporated by reference in its entirety.

BACKGROUND

[0002] Bitumen is a heavy type of crude oil that is often found in
naturally occurring geological materials such as tar sands, black shale,
coal formations, and weathered hydrocarbon formations contained in
sandstones and carbonates. Some bitumen may be described as flammable
brown or black mixtures or tarlike hydrocarbons derived naturally or by
distillation from petroleum. Bitumen can be in the form of anywhere from
a viscous oil to a brittle solid, including asphalt, tars, and natural
mineral waxes. Substances containing bitumen may be referred to as
bituminous, e.g., bituminous coal, bituminous tar, or bituminous pitch.
At room temperature, the flowability of some bitumen is much like cold
molasses. Bitumen may be processed to yield oil and other commercially
useful products, primarily by cracking the bitumen into lighter
hydrocarbon material.

[0003] As noted above, tar sands represent one of the well known sources
of bitumen. Tar sands typically include bitumen, water, and mineral
solids. The mineral solids can include inorganic solids such as coal,
sand, and clay. Tar sand deposits can be found in many parts of the
world, including North America. One of the largest North American tar
sands deposits is in the Athabasca region of Alberta, Canada. In the
Athabasca region, the tar sands formation can be found at the surface,
although it may be buried two thousand feet below the surface overburden
or more.

[0004] Tar sands deposits can be measured in barrels equivalent of oil.
The Athabasca tar sands deposit has been estimated to contain the
equivalent of about 1.7 to 2.3 trillion barrels of oil. Global tar sands
deposits have been estimated to contain up to 4 trillion barrels of oil.
By way of comparison, the proven worldwide oil reserves are estimated to
be about 1.3 trillion barrels.

[0005] The bitumen content of some tar sands may vary from approximately 3
wt % to 21 wt %, with a typical content of approximately 12 wt %.
Accordingly, an initial step in deriving oil and other commercially
useful products from bitumen typically can require extracting the bitumen
from the naturally occurring geological material. In the case of tar
sands, this may include separating the bitumen from the mineral solids
and other components of tar sands.

[0006] One conventional process for separating bitumen from mineral solids
and other components of tar sands includes mixing the tar sands with hot
water and, optionally, a process aid such as caustic soda (see, e.g.,
U.S. Pat. No. 1,791,797). Agitation of this mixture releases bitumen from
the tar sands and allows air bubbles to attach to the released bitumen
droplets. These air bubbles float to the top of the mixture and form a
bitumen-enriched froth. The froth can include around 60% bitumen, 30%
water, and 10% inorganic minerals. The bitumen-enriched froth is
separated from the mixture, sometimes with the aid of a solvent, and
further processed to isolate the bitumen product.

[0007] For example, the froth can be treated with an aliphatic
(pentane-type) or an aromatic (naphtha-type) solvent to produce a clean
bitumen product that can serve as a refinery upgrader feed stock. The
bulk of the mineral solids can also be removed to form a tailings stream.
The tailings stream can also include water, solvent, precipitated
asphaltenes (in the case where the asphaltene is not soluble in the
solvent used to separate the bitumen-enriched froth from the mixture),
and some residual bitumen.

[0008] Tailings produced by the hot water process and/or the froth
treatment process can pose several problems. Firstly, as noted above, the
tailings produced by conventional methods can include solvents,
precipitated asphaltenes, or residual bitumen. The bitumen and
asphaltenes in a tailings stream represent unrecovered hydrocarbon that
will not be processed into valuable commercial products. Accordingly, the
conventional methods can result in a lower yield of hydrocarbon material,
and consequently, diminished profit.

[0009] Additionally, the presence of bitumen and asphaltene in the
tailings can complicate the disposal of the tailings because these
materials present environmental risks. This can also be true for residual
solvent included in the tailings that can be environmentally unfriendly.

[0010] The amount of tailings produced by conventional methods can also
present chemical and physical problems. In some circumstances, the total
volume of the tailings produced by the conventional methods may be more
than the volume of mined tar sands, which means that not all of the
tailings can be returned to the mined area.

[0011] The physical characteristics of the tailings can also present
problems. The conventional methods sometimes utilize water and caustic as
part of the process. This can result in the activation and swelling of
certain clay components of a tailings stream. Accordingly, the tailings
can have a sludge-like consistency that may last indefinitely. The
sludge-like consistency means that the tailings are not stackable,
thereby limiting the manner in which to dispose of the tailings. Often
the only disposal option is to deposit the tailings in a tailings pond
located outside of the mine area. These ponds can be costly to build and
maintain and can be damaging to the local environment, including the
local water supply. Furthermore, ponds can be damaging to the local
wildlife population, such as birds, which can be caught in the oil and
solvent laden tailings produced by hot-water extraction processes.

SUMMARY

[0012] Disclosed are embodiments of a method for producing solvent-dry,
stackable tailings, and the solvent-dry, stackable tailings produced
therefrom.

[0013] In some embodiments, a method of extracting bitumen from bituminous
material is disclosed. The method includes passing a first solvent
through a first quantity of bituminous material, passing a second solvent
through the first quantity of bituminous material, and passing water
through the first quantity of bituminous material. The second solvent can
be a paraffinic solvent. The method can produce solvent-dry tailings due
at least in part to the inclusion of a water wash step that is capable of
effectively removing paraffinic solvent from the tailings produced during
the process. The solvent-thy tailings are beneficial because they are
easier to dispose of from an environmental standpoint.

[0014] In some embodiments, a method for extracting bitumen from
bituminous material is disclosed. The method includes mixing first
solvent with bituminous material and forming a mixture, separating the
mixture into a bitumen-enriched solvent phase and a bitumen-depleted
tailings phase, passing second solvent through the bitumen-depleted
tailings phase, passing third solvent through the bitumen-depleted
tailings phase, and passing water through the bitumen-depleted tailings
phase. The third solvent can be a paraffinic solvent. The method can
produce solvent-thy tailings due at least in part to the inclusion of a
water wash step that is capable of effectively removing paraffinic
solvent from the tailings produced during the process. The solvent-dry
tailings are beneficial because they are easier to dispose of from an
environmental standpoint.

[0015] In some embodiments, a method for extracting bitumen from
bituminous material is disclosed. The method includes contacting a
bituminous material with a first solvent and forming first solvent-wet
bituminous material, contacting the first solvent-wet bituminous material
with a second solvent and forming second solvent-wet bituminous material,
and contacting the second solvent-wet bituminous material with water and
forming a water-wet bituminous material, The second solvent can be a
paraffinic solvent. The method can produce solvent-dry tailings due at
least in part to the inclusion of a water wash step that is capable of
effectively removing paraffinic solvent from the tailings produced during
the process. The solvent-dry tailings are beneficial because they are
easier to dispose of from an environmental standpoint.

[0016] It is to be understood that the foregoing is a brief summary of
various aspects of some disclosed embodiments. The scope of the
disclosure need not therefore include all such aspects or address or
solve all issues noted in the Background above. In addition, there are
other aspects of the disclosed embodiments that will become apparent as
the specification proceeds.

[0017] Thus, the foregoing and other features, utilities, and advantages
of the subject matter described herein will be apparent from the
following more particular description of certain embodiments as
illustrated in the accompanying drawings. In this regard, it is therefore
also to be understood that the scope of the invention is to be determined
by the claims as issued and not by whether given subject includes any or
all features or aspects noted in this Summary or addresses any issues
noted in the Background.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The preferred and other embodiments are disclosed in association
with the accompanying drawings in which:

[0020] FIG. 2 is a schematic diagram for a system and method for producing
solvent-dry, stackable tailings as disclosed herein;

[0021] FIG. 3 is a schematic diagram for a system and method for producing
solvent-dry, stackable tailings as disclosed herein; and

[0022] FIG. 4 is a schematic diagram for a system and method for producing
solvent-dry, stackable tailings as disclosed herein.

DETAILED DESCRIPTION

[0023] Before describing the details of the various embodiments herein, it
should be appreciated that the terms "solvent," "a solvent" and "the
solvent" may include one or more than one individual solvent compounds
unless expressly indicated otherwise. Mixing solvents that include more
than one individual solvent compound with other materials can include
mixing the individual solvent compounds simultaneously or serially unless
indicated otherwise. It should also be appreciated that the term "tar
sands" includes oil sands. The separations described herein can be
partial, substantial or complete separations unless indicated otherwise.
All percentages recited herein are volume percentages unless indicated
otherwise.

[0024] Tar sands are used throughout this disclosure as a representative
bitumen material. However, the methods and systems disclosed herein are
not limited to processing of tar sands. Applicant believes that any
bitumen material may be processed by the methods and systems disclosed
herein.

[0025] With reference to FIG. 1, one embodiment of a method for producing
solvent-dry, stackable tailings includes a step 100 of adding a first
quantity of first solvent to a bitumen material to form a first mixture,
a step 110 of separating a first quantity of bitumen-enriched solvent
phase from the first mixture, a step 120 of adding a quantity of second
solvent to the first solvent-wet tailings, and a step 130 of adding a
quantity of water to the second solvent-wet tailings.

[0026] Step 100 of adding a first quantity of first solvent to bitumen
material to form a first mixture represents a step in the solvent
extraction process (also sometimes referred to as dissolution, solvation,
or leaching). Solvent extraction is a process of separating a substance
from a material by dissolving the substance of the material in a liquid.
In this situation, the bitumen material is mixed with one or more
solvents to dissolve bitumen in the solvent and thereby separate it from
the other components of the bitumen material (e.g., the mineral solids of
tar sands).

[0027] The first solvent used in step 100 can include a hydrocarbon
solvent. Any suitable hydrocarbon solvent or mixture of hydrocarbon
solvents that is capable of dissolving bitumen can be used. In some
embodiments, the hydrocarbon solvent is a hydrocarbon solvent that does
not result in asphaltene precipitation. The hydrocarbon solvent or
mixture of hydrocarbon solvents can be economical and relatively easy to
handle and store. The hydrocarbon solvent or mixture of hydrocarbon
solvents may also be generally compatible with refinery operations.

[0028] In some embodiments, the first solvent is a light aromatic solvent.
The light aromatic solvent can be an aromatic compound having a boiling
point temperature less than about 400° C. at atmospheric pressure.
In some embodiments, the light aromatic solvent used in the first mixing
step is an aromatic having a boiling point temperature in the range of
from about 75° C. to about 350° C. at atmospheric pressure,
and more specifically, in the range of from about 100° C. to about
250° C. at atmospheric pressure. In some embodiments, the aromatic
has a boiling point temperature less than 200° C.

[0029] It should be appreciated that the light aromatic solvent need not
be 100% aromatic compounds. Instead, the light aromatic solvent can
include a mixture of aromatic and non-aromatic compounds. For example,
the first solvent can include greater than zero to about 100 wt %
aromatic compounds, such as approximately 10 wt % to 100 wt % aromatic
compounds, or approximately 20 wt % to 100 wt % aromatic compounds.

[0030] Any of a number of suitable aromatic compounds can be used as the
first solvent. Examples of aromatic compounds that can be used as the
first solvent include benzene, toluene, xylene, aromatic alcohols, and
combinations and derivatives thereof. The first solvent can also include
compositions, such as kerosene, diesel (including biodiesel), light gas
oil, light distillate (distillate having boiling point temperature in the
range of from 140° C. to 260° C.), commercial aromatic
solvents such as Aromatic 100, Aromatic 150, and Aromatic 200, and/or
naphtha. In some embodiments, the first solvent has a boiling point
temperature of approximately 75° C. to 375° C. Naphtha, for
example, is particularly effective at dissolving bitumen and is generally
compatible with refinery operations.

[0031] The first solvent added into the bitumen material in step 100 need
not be 100% first solvent. Other components can be included with the
first solvent when it is added into the bitumen material. In some
embodiments, the first solvent added into the column includez a bitumen
content. First solvent including a bitumen content can be referred to as
bitumen-enriched first solvent, dissolved bitumen ("disbit"), or diluted
bitumen ("dilbit"). Bitumen-enriched first solvent can be obtained from
bitumen extraction processes where a first solvent has already been used
to extract bitumen from bitumen material. In some embodiments, the
bitumen-enriched first solvent is bitumen-enriched solvent separated from
the first mixture in step 110 described in greater detail below and
recycled back within the method for use in step 100.

[0032] The bitumen material used in step 100 can be any material that
includes bitumen. In some embodiments, the bitumen material includes any
material having more than 3 wt % bitumen. Exemplary bitumen materials
include, but are not limited to, tar sands, black shales, coal
formations, and hydrocarbon sources contained in sandstones and
carbonates. The bitumen material can be obtained by any known methods for
obtaining bitumen material, such as by surface mining, underground
mining, or any in situ extraction methods, such as vapor extraction
(Vapex) and steam assisted gravity drainage (SAGD) extraction.

[0033] In some embodiments, the bitumen material is subjected to one or
more pretreatment steps prior to being mixed with the first solvent. Any
type of pretreatment step that will promote mixing between the first
solvent and bitumen material and/or promote extraction of bitumen from
the bitumen material can be used. In some embodiments, the pretreatment
step involves heating the bitumen material. In some embodiments, the
bitumen material is heated to a temperature in the range of from
30° C. to 40° C. Any manner of heating the bitumen material
can be used in the pretreatment step. In some embodiments, the bitumen
material is heated by adding hot water or steam to the bitumen material.
Immersed heaters can also be used to heat the bitumen material.

[0034] While some embodiments include a bitumen material heating
pretreatment step as described above, other embodiments specifically
exclude any bitumen material heating pretreatment steps. In such
embodiments, the bitumen material is mixed with the first solvent at the
naturally occurring temperature of the bitumen material prior to mixing.
The method can thereby eliminate the cost associated with heating the
bitumen and simplify the overall method. In some embodiments the solvent
is heated or retains heat from the previous recovery steps in recovering
solvent from the bitumen.

[0035] The step of adding a first quantity of first solvent to the bitumen
material to form a mixture can be performed as a continuous, batch, or
semi-batch process. Continuous processing may typically be used in larger
scale implementations. However, batch processing may result in more
complete separations than continuous processing.

[0036] The first solvent can be added to the bitumen material by any
suitable manner for ultimately forming a mixture of the two components.
For example, the first solvent can be added to the bitumen material by
mixing the two components together. The mixing of the bitumen material
and the first solvent is preferably carried out to the point of
dissolving most, if not all, of the bitumen contained in the bitumen
material. In some embodiments, the bitumen material and the first solvent
are mixed in a vessel to dissolve the bitumen and form the first mixture.
The vessel can be selectively opened or closed. The vessel used for
mixing can also contain mechanisms for stirring and mixing solvent and
bitumen material to further promote dissolution of the bitumen in the
first solvent. For example, powered mixing devices such as a rotating
blade may be provided to mix the contents of the vessel. In another
example, the vessel itself may be rotated to cause mixing between the
bitumen material and the first solvent, such as shown in U.S. Pat. No.
5,474,397.

[0037] In certain embodiments, bitumen material and the first solvent are
mixed by virtue of the manner in which the bitumen material and the first
solvent are introduced into the vessel. That is to say, the first solvent
is introduced into a vessel already containing bitumen material at a high
velocity, thereby effectively agitating and mixing the contents of the
vessel. Conversely, the bitumen material can be introduced into a vessel
already containing first solvent.

[0038] The amount of the first solvent added to the bitumen material can
be a sufficient amount to effectively dissolve at least a portion, or
desirably all of the bitumen in the bitumen material. In some
embodiments, the amount of the first solvent mixed with the bitumen
material is approximately 0.5 to 3.0 times the amount of bitumen by
volume contained in the bitumen material, approximately 0.6 to 2.0 times
the amount of the bitumen by volume contained in the bitumen material, or
preferably approximately 0.75 to 1.5 times the amount of bitumen by
volume contained in the bitumen material.

[0039] It should be noted that the ratio of the first solvent to bitumen
can be affected by the amount of bitumen in the bitumen material. For
example, more solvent may be required for lower grade tars sands ore
(e.g., 6 wt % bitumen) than for average grade tar sands ore (e.g.,
between 9 wt % and 14 wt % bitumen). Conversely, very high grade tar
sands ore (e.g., greater than 15 wt % bitumen) may require a higher
solvent to bitumen ratio again.

[0040] The first mixture of the first solvent and the bitumen material
generally includes bitumen-enriched solvent, with the majority of the
bitumen from the bitumen material dissolved in the bitumen-enriched
solvent phase. In some embodiments, 90%, preferably 95%, and most
preferably 99% or more of the bitumen in the bitumen material is
dissolved in the first solvent and becomes part of the bitumen-enriched
solvent.

[0041] The bitumen-enriched solvent is separated from the first mixture at
step 110. Separation of the bitumen-enriched solvent from the first
mixture may result in the first mixture becoming first solvent-wet
tailings when a portion of the first solvent remains behind in the
non-bituminous components of the first mixture after separation of
bitumen-enriched solvent. Any suitable process for separating the
bitumen-enriched solvent from the first mixture can be used, such as by
filtering bitumen-enriched solvent from the first mixture (including but
not limited to filtration via an automatic pressure filter, vacuum
filtration, pressure filtration, and crossflow filtration), settling the
first mixture and decanting bitumen-enriched solvent off the top of the
settled mixture, by gravity or gas overpressure drainage of the
bitumen-enriched solvent from the first mixture, or by displacement
washing of the bitumen-enriched solvent from the first mixture. Any of
these separation methods can be used alone or in combination to separate
bitumen-enriched solvent from the first mixture.

[0042] In some embodiments, the bitumen-enriched solvent removed from the
first mixture includes from about 5 wt % to about 50 wt % of bitumen and
from about 50 wt % to about 95 wt % of the first solvent. The
bitumen-enriched solvent may include little or no non-bitumen components
of the bitumen material (e.g., mineral solids). The first solvent-wet
tailings created by removing the bitumen-enriched solvent from the first
mixture can include from about 75 wt % to about 95 wt % non-bitumen
components and from about 5 wt % to about 25 wt % first solvent. The
first solvent component of the first solvent-wet tailings represents
first solvent mixed with the bitumen material but which is not removed
from the first mixture during separation step 110. This first solvent
component of the first solvent-wet tailings can have bitumen dissolved
therein. Accordingly, in some embodiments, the first solvent-wet tailings
includes from about 1 wt % to about 5 wt % of bitumen.

[0043] The vessel for mixing mentioned previously can function as both a
mixer and a separator for separating the bitumen-enriched solvent from
the first mixture. Alternatively, separate vessels can be used for mixing
and separating, wherein the first mixture is transported from the mixing
vessel to a separation vessel. In some embodiments, the vessel is divided
into sections. One section may be used to mix the bitumen material and
the first solvent and another section may be used to separate the
bitumen-enriched solvent from the first mixture.

[0044] The separation of the bitumen-enriched solvent from the first
mixture can be performed as a continuous, batch, or semi-batch process.
Continuous processing may typically be used in larger scale
implementations. However, batch processing may result in more complete
separations than continuous processing.

[0045] Separation of the bitumen-enriched solvent from the first mixture
by any of the above-mentioned methods can be preceded or followed by
applying pressurized gas over the first mixture. Applying a pressurized
gas over the first mixture can facilitate the separation of the
bitumen-enriched solvent from the non-bitumen components of the first
solvent-wet tailings. Bitumen-enriched solvent entrained between solid
sand particles can then be removed by applying additional first solvent
to the first solvent-wet tailings as described in greater detail below.
The addition of additional first solvent can displace the liberated
bitumen-enriched solvent from the first solvent-wet tailings by providing
a driving force across a filtration element (i.e., the non-bituminous
components of the bitumen material). Any suitable gas capable of
displacing solvent can be used. In some embodiments, the gas is nitrogen,
carbon dioxide, or steam. The gas can also be added over the first
mixture in any suitable amount. In some embodiments, 1.8 m3 to 10.6
m3 of gas per ton of bitumen material is used. This is equivalent to
a range of about 4.5 liters to 27 liters of gas per liter of bitumen
material. In certain embodiments, 3.5 ft3 of gas per ton of bitumen
material is used.

[0046] Bitumen-enriched solvent separated during step 110 can be subjected
to further processing to separate the first solvent from the bitumen. Any
suitable method of separating the two components can be used. In some
embodiments, the bitumen-enriched solvent is heated to a temperature
above the boiling temperature of the first solvent, resulting in the
first solvent evaporating off of the bitumen. The evaporated first
solvent can be collected, condensed, and recycled back in the extraction
process.

[0047] After bitumen-enriched solvent has been separated from the first
mixture and first solvent-wet tailings have been produced as a result, a
step 120 of adding a quantity of second solvent to the first solvent-wet
tailings is carried out in order to remove first solvent from the first
solvent-wet tailings. Addition of the second solvent can displace the
first solvent component and force the first solvent out of the first
solvent-wet tailings. As noted above, the first solvent-wet tailings can
include from about 5 wt % to about 20 wt % of the first solvent, and it
is desirable to remove this first solvent from the tailings to make the
tailings more environmentally friendly. In some embodiments, the first
solvent also has some bitumen dissolved therein, which will also be
displaced from the solvent-wet tailings.

[0048] The second solvent can be any suitable solvent that is useful for
displacing the first solvent. In some embodiments, the second solvent has
a higher vapor pressure than the first solvent to enhance removal of the
second solvent in subsequent processing steps. In some embodiments, the
second solvent is a hydrocarbon solvent. Any suitable hydrocarbon solvent
or mixture of hydrocarbon solvents that is capable of displacing the
first solvent can be used. The hydrocarbon solvent or mixture of
hydrocarbon solvents can preferably be economical and relatively easy to
handle and store. The hydrocarbon solvent or mixture of hydrocarbon
solvents may also be generally compatible with refinery operations. The
hydrocarbon solvent or mixture of hydrocarbon solvents may also generally
have a boiling point below that of water to facilitate solvent removal
and recovery at lower energy input.

[0049] In some embodiments, the second solvent is a polar solvent. The
polar solvent added to the first solvent-wet tailings can be any suitable
polar solvent that is capable of displacing the first solvent. In some
embodiments, the polar solvent is an oxygenated hydrocarbon. Oxygenated
hydrocarbons include any hydrocarbons having an oxygenated functional
group. Oxygenated hydrocarbons include alcohols, ketones, and ethers.
Oxygenated hydrocarbons as used in the present application do not include
alcohol ethers or glycol ethers.

[0050] Suitable alcohols for use as the polar solvent include methanol,
ethanol, propanol, and butanol. The alcohol can be a primary (e.g.,
ethanol), secondary (e.g., isopropyl alcohol) or tertiary alcohol (e.g.,
tert-butyl alcohol).

[0051] As noted above, the polar solvent can also be a ketone. Generally,
ketones are a type of compound that contains a carbonyl group (C═O)
bonded to two other carbon atoms in the form: R1(CO)R2. Neither of the
substituents R1 and R2 may be equal to hydrogen (H) (which would make the
compound an aldehyde). A carbonyl carbon bonded to two carbon atoms
distinguishes ketones from carboxylic acids, aldehydes, esters, amides,
and other oxygen-containing compounds. The double-bond of the carbonyl
group distinguishes ketones from alcohols and ethers. The simplest ketone
is acetone, CH3-CO-CH3 (systematically named propanone).

[0052] When the second solvent is a polar solvent, issues can arise
regarding the ability of the polar solvent to mix with first solvent (and
bitumen dissolved therein) contained in the first solvent-wet tailings.
Such issues may arise when the first solvent-wet tailings include a
certain water content. Water may be present in the first solvent-wet
tailings due to water content already present in the bitumen material
when preparing the first mixture. If a sufficient amount of water is
present in the first solvent-wet tailings, the polar solvent may mix with
the water to form a homogenous mixture due to their common polar nature.
However, once the polar solvent and water have mixed together, the
mixture may then be immiscible with the first solvent due to the
non-polar nature of the first solvents used in the method described
herein. In such a scenario, the mixture of water and polar solvent may be
repelled by the first solvent and no longer serve as a chemical solvent
but only as a first solvent physical displacement agent. It may therefore
be useful in some embodiments to monitor and/or control the water content
of the bitumen material and first solvent-wet tailings used in the method
described herein in order to avoid possible problems associated with the
differences in polarity between the various solvents and displacement
agents.

[0053] Adding second solvent to the first solvent-wet tailings can be
carried out in any suitable manner that results in first solvent
displacement from the first solvent-wet tailings. The amount of the
second solvent added to the first solvent-wet tailings can be sufficient
to effectively displace at least a portion, or desirably all, of the
first solvent in the first solvent-wet tailings. The amount of second
solvent added to the first solvent-wet tailings can be approximately 0.5
to 4 times the amount of bitumen by volume originally contained in the
bitumen material.

[0054] In some embodiments, the addition of second solvent to the first
solvent-wet tailings results in the removal of 95% or more of the first
solvent in the first solvent-wet tailings. The first solvent can leave
the first solvent-wet tailings as a first solvent-second solvent mixture.
The first solvent-second solvent mixture can include from about 5 wt % to
about 50 wt % first solvent and from about 50 wt % to about 95 wt %
second solvent. The removal of the first solvent from the first
solvent-wet tailings through the addition of second solvent can result in
a quantity of second solvent not passing all the way through the first
solvent-wet tailings. Accordingly, the first solvent-wet tailings can
become a second solvent-wet tailings upon separation of the first
solvent. In some embodiments, the second solvent-wet tailings includes
from about 70 wt % to about 95 wt % non-bitumen components and from about
5 wt % to about 30 wt % second solvent.

[0055] The first solvent-second solvent mixture can be collected so that
the first solvent and second solvent may be separated and reused in the
extraction process. Any suitable manner of separating the first solvent
from the second solvent can be used, including but not limited to,
separation through heating, phase separation, and physical separation. In
some embodiments, the mixture is heated to a temperature above the
boiling temperature of one of the solvents but below the boiling
temperature of the other solvent. In this manner, one solvent evaporates
off the other solvent. The evaporated solvent can be collected,
condensed, and reused in the extraction process. In some embodiments
where the second solvent is a polar solvent, separation of the first
solvent and the second solvent occurs naturally via phase separation or
can be manipulated via control of the water content. Further descriptions
separating mixtures of first solvents and polar second solvents through
natural phase separation are set forth in co-pending U.S. application
Ser. No. 12/560,964, herein incorporated by reference in its entirety.

[0056] As with previously described separation steps, separation of the
first solvent from the first solvent-wet tailings by adding second
solvent can be preceded or followed by applying pressurized gas over the
first solvent-wet tailings. Applying a pressurized gas over the first
solvent-wet tailings can facilitate the separation of the first solvent
component of the first solvent-wet tailings from the non-bitumen
components of the first solvent-wet tailings. The liberated first solvent
can then be displaced from the first solvent-wet tailings by applying
additional second solvent to the first solvent-wet tailings. The
application of a gas overpressure can also displace first solvent from
the first solvent-wet tailings by providing a driving force across a
filtration element (i.e., the non-bituminous components of the first
solvent-wet tailings). Any suitable gas for displacing solvent can be
used. In some embodiments, the gas is nitrogen, carbon dioxide or steam.
The gas can also be added over the second mixture in any suitable amount.
In some embodiments, 1.8 m3 to 10.6 m3 of gas per ton of
bitumen material is used. This is equivalent to a range of about 4.5
liters to 27 liters of gas per liter of bitumen material. In certain
embodiments, 3.5 ft3 of gas per ton of bitumen material is used.

[0057] In step 130, water is added to the second solvent-wet tailings to
remove second solvent from the second solvent-wet tailings and thereby
produce solvent-dry, stackable tailings. The addition of water to the
second solvent-wet tailings can serve to displace the second solvent from
the second solvent-wet tailings and force the second solvent out of the
second solvent-wet tailings. In some embodiments, the addition of water
results in the removal of 95 wt % or more of the second solvent from the
second solvent-wet tailings.

[0058] Any manner of adding water to the second solvent-wet tailings that
results in displacement of second solvent from the second solvent-wet
tailings can be used. In some embodiments, the manner in which the water
is added to the second solvent-wet tailings is similar or identical to
the manner in which the first solvent is added to the first mixture or
the second solvent is added to the first solvent wet tailings.

[0059] In some embodiments, water with an elevated temperature (i.e.,
above room temperature) or steam is used to displace second solvent from
second-solvent wet tailings. Water with an elevated temperature can
preferably be at a temperature greater than the boiling point temperature
of the second solvent. When water at an elevated temperature or steam is
used, the introduction of the water or steam into the second solvent-wet
tailings can serve to both displace the second solvent and remove second
solvent via evaporation. For example, steam may rapidly condense once
introduced into the second solvent-wet tailings and transfer heat to the
second solvent, resulting in second solvent evaporation. Water at an
elevated temperature can be added with the second solvent-wet tailings in
the same manner as water at room temperature. Steam can be injected into
the second solvent-wet tailings. Any manner for injecting steam into the
second solvent-wet tailings can be used. In some embodiments, injection
lines are inserted into the second solvent-wet tailings through which
steam can be injected into the second solvent-wet tailings.

[0060] The amount of the water or steam added to the second solvent-wet
tailings can be sufficient to effectively displace and/or evaporate at
least a portion, or desirably all, of the second solvent in the second
solvent-wet tailings. The amount of water added to the second solvent-wet
tailings can be approximately 0.5 to 4 times the amount of bitumen by
volume originally contained in the bitumen material. The amount of steam
added to the second solvent-wet tailings can be approximately less than
or equal to 2 times the amount of bitumen by volume originally contained
in the bitumen material.

[0061] In some embodiments, the water is added in two or more stages, with
the water being in the same or different phases for each stage. For
example, in some embodiments, a first stage addition of water includes
the addition of water in a liquid phase, and a second stage addition of
water includes the addition of steam. When water in a liquid phase is
used for any stage, the water can be at any suitable temperature,
including water at elevated temperatures.

[0062] In embodiments where polar solvents are used as the second solvent,
the step 130 of adding water to the second solvent-wet tailings can be
especially effective at removal of the polar second solvent. This may be
due to the miscibility of many polar solvents in water. The water can
form a homogenous mixture with the polar solvent as it passes through the
second-solvent wet tailings, resulting in effective removal of second
solvent.

[0063] Water used to displace second solvent from the second solvent-wet
tailings can exit the second solvent-wet tailings in a mixture with
displaced second solvent. The mixture of water and second solvent can be
collected and separated so that the water and second solvent can be
reused in the extraction method. Any suitable method for separating the
water and second solvent can be used. In some embodiments, the water and
second solvent are separated based on differences in boiling
temperatures. In embodiments where certain polar solvents (such as
methanol) are used, no azeotrope between the polar solvent and water
exists, thus making the separation of the water and polar solvent by
heating a viable mechanism for separation. If azeotropes are formed, the
azeotropic solution can be used as a solvent for a washing step performed
after completion of the washing step with the second solvent but prior to
the washing step with water. Polar solvents (such as methanol) and water
can also be separated using membrane-based pervaporation, which is an
energy efficient combination of membrane permeation and evaporation.

[0064] In some embodiments, the water and second solvent exiting the
second solvent-wet tailings may also include residual first solvent. The
residual first solvent can be included with the second solvent and water
in situations where the addition of second solvent to the first
solvent-wet tailings does not fully displace all of the first solvent
from the tailings. In some embodiments, the residual first solvent is
disbit. In embodiments where the second solvent is a polar solvent, the
mixture of water, polar solvent, and first solvent exiting the second
solvent-wet tailings can phase separate due to the common polarity of the
water and polar solvent and the non-polar nature of the first solvent.
More specifically, the polar solvent will be miscible in the water and
form a homogenous mixture, while the first solvent will be repelled from
the homogenous mixture due to the differences in polarity. In such a
scenario, the first solvent component of the mixture exiting the second
solvent-wet tailings can be separated from the homogenous mixture of
water and polar solvent using relatively simple and inexpensive
separation methods (e.g., decanting), as opposed to a more complicated
and expensive separation process (e.g., distillation) that is
traditionally required when phase separation has not occurred.

[0065] The solvent-dry, stackable tailings resulting from removal of the
second solvent from the second solvent-wet tailings generally include
inorganic solids, such as sand and clay, water, and little to no first
and second solvent. As used herein, the term "solvent-thy" means
containing less than 0.1 wt % total solvent. As used herein, the term
"stackable" means having a water content of from about 2 wt % to about 15
wt %. This range of water content can create damp tailings that will not
produce dust when transporting or depositing the tailings. This range of
water content can also provide stackable tailings that will not flow like
dry sand, and therefore have the ability to be retained within an area
without the need for retaining structures (e.g., a tailings pond). This
range of water content can also provide tailings that are not so wet as
to be sludge-like or liquid-like. The solvent-dry, stackable tailings
produced by the above described method can also include less than 2 wt %
bitumen.

[0066] Generally speaking, the above-described process can be considered
advantageous over the previously known hot water bitumen extraction
process because water is used to remove solvent rather than to extract
bitumen from bitumen material. In Applicant's experience, water displaces
solvent more easily than it extracts bitumen. Additionally, avoiding the
use of water to extract bitumen can mitigate or eliminate many of the
problems discussed in greater detail above.

[0067] In some embodiments, the above, described method may be carried
with the use of a plate and frame-type filter press. After performing
step 100 of mixing first solvent with bitumen material, the first mixture
may be loaded into a plate and frame-type filter press, at which point
the separation and addition steps 110, 120, and 130 may be carried out.

[0068] The plate and frame-type filter press may be any suitable type of
plate and frame-type filter press, including both vertical and horizontal
plate and frame-type filter presses. An exemplary vertical plate and
frame-type filter press suitable for use in this method is described in
U.S. Pat. No. 4,222,873. An exemplary horizontal plate and frame-type
filter press suitable for use in this method is described in U.S. Pat.
No. 6,521,135. Generally, the first mixture may be pumped into frame
chamber located between two filter plates. The first mixture fills the
frame chamber and, as the frame chamber becomes fully occupied by the
first mixture, separation step 110 takes place as liquid bitumen-enriched
solvent migrates out of the frame chamber through the filter cloths of
each filter plate. The solid material of the first mixture remains behind
in the frame chamber.

[0069] Separation of the bitumen-enriched solvent from the first mixture
may also take place by adding additional first solvent into the filter
press after loading the first mixture into the frame chamber. The
additional first solvent pumped into the frame chamber may serve to
displace bitumen-enriched solvent from the frame chamber and through the
filter cloths. Any suitable amount of additional first solvent that will
displace bitumen-enriched solvent from the frame chamber may be
introduced into the frame chamber. The first solvent may be the same
first solvent used when forming the first mixture in step 100 or may be
another type of first solvent as described in greater detail above (e.g.,
a different light aromatic solvent from the light aromatic solvent mixed
with the bitumen material).

[0070] The addition of second solvent and water to separate first solvent
and second solvent, respectively, can proceed in a similar or identical
fashion to the addition of first solvent into the frame chamber as
described above. The addition of second solvent into the frame chamber
loaded with first solvent-wet tailings can displace first solvent through
the filter cloths and out of the frame chamber. Similarly, the addition
of water into the frame chamber loaded with second solvent-wet tailings
can displace second solvent through the filter cloths and out of the
frame chamber.

[0071] When utilizing a filter press to carry out the method described
herein, pressurized gas can be injected into the frame chamber before or
after the addition of the first mixture, the first solvent, the second
solvent, or the water. The addition of the pressurized gas can help
promote the separation of the materials targeted for separation by, e.g.,
liberating the material from the mineral solids so that it may more
freely be removed upon subsequent addition of a displacement liquid. The
introduction of pressurized gas into the frame chamber can proceed
according to the details provided above for applying pressurized gas over
a first mixture.

[0072] In some embodiments, the above described method is carried out by
utilizing countercurrent washing. After step 100 of adding first solvent
to bitumen material to form a first mixture, the separation and addition
steps 110, 120, and 130 can take place by moving the various materials
through each other in opposite directions. For example, with respect to
step 110, the separation step can be carried out by performing a
countercurrent washing process where first solvent traveling in one
direction is passed through the first mixture traveling in an opposite
direction. In some embodiments, the first mixture is loaded at the bottom
of a screw classifier conveyor positioned at an incline, while a second
quantity of first solvent may be introduced at the top of the screw
classifier conveyor. An exemplary screw classifier conveyor suitable for
use in this method is described in U.S. Pat. No. 2,666,242. As the screw
classifier conveyor moves the first mixture upwardly, the second quantity
of first solvent flows down the inclined screw classifier conveyor and
pass through the first mixture. The second quantity of first solvent can
displace bitumen-enriched solvent contained in the first mixture, thereby
"washing" the bitumen-enriched solvent from the first mixture.

[0073] Separation of the bitumen-enriched solvent and the first mixture
may naturally occur based on the configuration of the screw classifier
conveyor, with the predominantly liquid bitumen-enriched solvent
collecting at one end of the washing unit and the predominantly solid
first solvent-wet tailings at the opposite end of the washing unit. For
example, when an inclined screw classifier conveyor is used, the
bitumen-enriched solvent can collect at the bottom of the screw
classifier conveyor, while the first solvent-wet tailings can collect at
the top of the screw classifier conveyor. The bitumen-enriched solvent
can include predominantly bitumen and first solvent.

[0074] The countercurrent process can include multiple stages. For
example, after a first pass of first solvent through the first mixture,
the resulting bitumen-enriched solvent can be passed through the
resulting first solvent-wet tailings several more times. Alternatively,
additional quantities of fresh first solvent can be passed through the
resulting first solvent-wet tailings one or more times. In this manner,
the bitumen-enriched solvent or fresh quantities of first solvent can
become progressively more enriched with bitumen after each stage and the
first solvent-wet tailings can lose progressively more bitumen after each
stage.

[0075] Steps 120 and 130 can be carried out in a similar fashion. The
first solvent-wet tailings obtained after washing the first mixture in a
countercurrent process can be subjected to a countercurrent washing with
second solvent. As the second solvent passes through the first
solvent-wet tailings traveling in an opposite direction, the second
solvent displaces the first solvent. Subsequently, the second solvent-wet
tailings obtained after washing the first solvent-wet tailings in a
countercurrent process can be subjected to a countercurrent washing with
water. As the water passes through the second solvent-wet tailings
traveling in an opposite direction, the water displaces the second
solvent.

[0076] In some embodiments, the above described method is carried out by
utilizing a vertical column. The first mixture prepared in step 100 can
be loaded in a vertical column. Any method of loading the first mixture
in the vertical column can be used. First mixture can be poured into the
vertical column or, when an appropriate first mixture viscosity is
obtained from mixing step 100, the first mixture can be pumped into the
vertical column. First mixture can generally be loaded in the vertical
column by introducing the first mixture into the column at the top end of
the vertical column. The bottom end of the vertical column can be
blocked, such as by a removable plug, valve, or by virtue of the bottom
end of the vertical column resting against the floor. In some
embodiments, a metal filter screen at the bottom end of the vertical
column is used to maintain the first mixture in the vertical column.
Accordingly, introducing first mixture at the top end of the vertical
column can fill the vertical column with first mixture. The amount of
first mixture loaded in the vertical column may be such that the first
mixture substantially fills the vertical column with first mixture. In
some embodiments, first mixture is added to the vertical column to occupy
90% or more of the volume of the vertical column. In some embodiments,
the first mixture is not filled to the top of the vertical column so that
room is provided to inject first solvent, second solvent, etc., into the
vertical column.

[0077] In some embodiments, a pre-loading separation step is carried out
after the mixture has been prepared in step 100 but before the mixture is
loaded in the vertical column. The pre-loading separation step can
include separating a liquid component of the first mixture from the first
mixture. The liquid component can include a quantity of the
bitumen-enriched first solvent that is produced upon mixing the first
solvent and the bitumen material to form the first mixture. Because this
liquid component is accessible immediately upon formation of the first
mixture and relatively easy to separate from the first mixture using
basic separation techniques, it can be separated from the first mixture
prior to performing the further separation steps that occur in the
vertical column and which are primarily aimed at separating the more
inaccessible quantities of the bitumen-enriched solvent included in the
first mixture.

[0078] The liquid component of the first mixture can be separated from the
first mixture prior to loading the first mixture in the column by any
suitable separation method capable of separating a liquid component from
a first mixture. In some embodiments, any type of filtration process can
be used wherein the liquid component passes through a filtration medium
that does not allow solid particles of a certain size to pass
therethrough. Accordingly, when filtration is performed, the liquid
component including bitumen-enriched solvent passes through the filter
while bitumen material having some bitumen-enriched solvent entrained
therein will not pass through the medium. In other embodiments, the
liquid component is separated by decanting the first mixture. When
contained within a vessel, the first mixture can include a liquid
component that resides above the bitumen material. Accordingly, the
liquid component can be poured or skimmed off the top of the first
mixture to separate the liquid component from the remainder of the first
mixture.

[0079] In some embodiments where this pre-loading separation step is
carried out, the amount of first solvent added to the bitumen material to
form the first mixture is more than is added when a pre-loading
separation step is not performed. The aim of adding this higher amount of
solvent is to create a liquid component that is plentiful in the first
mixture and relatively easy to access for purposes of separation from the
first mixture. In some embodiments, an amount 1.5 to 3 times the typical
amount of first solvent is used to ensure that the pre-loading separation
step may be carried out.

[0080] As mentioned previously, the first solvent used in step 100 to form
the first mixture can be disbit. In some embodiments, the first solvent
used to form the first mixture is preferably disbit when a pre-loading
separation step is to be carried out.

[0081] As noted above, the column can have a generally vertical
orientation. The vertical orientation can include aligning the column
substantially perpendicular to the ground, but also can include
orientations where the column forms angles less than 90° with the
ground. The column can generally be oriented at any angle that results in
gravity aiding the flow of the first solvent, second solvent, etc., from
one end of the column to the other. In some embodiments, the column is
oriented at an angle anywhere within the range of from about 1° to
90° with the ground. In a preferred embodiment, the column is
oriented at an angle anywhere within the range of from about 15°
to 90° with the ground.

[0082] The material of the vertical column is also not limited. Any
material that will hold the first mixture within the vertical column can
be used. The material can also preferably be a non-porous material such
that various liquids injected into the vertical column only exit the
column from one of the ends of the vertical column. The material can be a
corrosive resistant material so as to withstand the potentially corrosive
components of the first mixture loaded in the column as well as any
potentially corrosive materials injected into the vertical column.

[0083] The shape of the vertical column is not limited to a specific
configuration. Generally speaking, the vertical column can have two ends
opposite one another, designated a top end and a bottom end. The
cross-section of the vertical column can be any shape, such as a circle,
oval, square or the like. The cross-section of the vertical column can
change along the height of the column, including both the shape and size
of the vertical column cross-section. The vertical column can be a
straight line vertical column having no bends or curves along the height
of the vertical column. Alternatively, the vertical column can include
one or more bends or curves.

[0084] Any dimensions can be used for the vertical column, including the
height, inner cross sectional diameter and outer cross sectional diameter
of the vertical column. In some embodiments, the ratio of height to inner
cross sectional diameter ranges from 0.5:1 to 15:1.

[0085] Once first mixture is loaded in the vertical column, the separation
and addition steps 110, 120, and 130 are carried out. With respect to
step 110, separation of the bitumen-enriched solvent from the first
mixture loaded in the column can be accomplished by adding a second
quantity of first solvent into the vertical column. The second quantity
of first solvent can be added into the vertical column at either the top
end of the column (down flow mode) or the bottom end of the column (up
flow mode). When a down flow mode is used, the second quantity of first
solvent flows downwardly through the first mixture loaded in the column.
As the second quantity of first solvent flows downwardly through the
column, it can displace bitumen-enriched solvent from the column. When an
up flow mode is used, the second quantity of first solvent flows upwardly
through the first mixture loaded in the column. As the second quantity of
first solvent flow upwardly through the column, it can dissolve further
bitumen contained in the first mixture and displace bitumen-enriched
solvent in the first mixture. A gas overpressure as described in greater
detail above, can then be used to displace the dissolved bitumen and
first solvent back down through the first mixture and out of the column.

[0086] The second quantity of first solvent can be added into the vertical
column by any suitable method. In some embodiments, the second quantity
of first solvent is poured or pumped into the vertical column at the top
end and allowed to flow down through the first mixture loaded therein
under the influence of gravity. In some embodiments, the second quantity
of the first solvent is pumped into the column from the bottom end of the
column. External pressures can also be added to promote the downward flow
of the first solvent after it has been added into the vertical column.

[0087] In some embodiments, the second quantity of first solvent is added
to the vertical column under flooded conditions. In other words, more
first solvent is added to the top of the vertical column than what flows
down through the first mixture, thereby creating a head of solvent at the
top of the vertical column.

[0088] Upon addition into the column in a down flow mode, the first
solvent can flow downwardly through the height of the column via small
void spaces in the first mixture. The first solvent can flow downwardly
through the force of gravity or by an external force applied to the
vertical column. Examples of external forces applied include the
application of pressure from the top of the vertical column or the
application of suction at the bottom of the vertical column. The first
solvent can travel the flow of least resistance through the first
mixture. As the first solvent flows downwardly through the first mixture,
bitumen enriched solvent contained in the first mixture can be displaced
downwardly through the column.

[0089] Upon addition into the column in an up flow mode, the first solvent
flows upwardly through the height of, the column via small void spaces in
the first mixture. The first solvent can flow upwardly through the
continuous pumping of first solvent into the column from the bottom end
of the column. As the first solvent flows upwardly through the first
mixture, bitumen in the first mixture may be dissolved and
bitumen-enriched solvent contained in the first mixture may be displaced
upwardly. After the first solvent has been added to the column in an up
flow mode, the dissolved bitumen and solvent can flow downwardly back
through the column as described above in the down flow mode. The force
acting on the dissolved bitumen and solvent can either be gravity or an
external force, such as a gas overpressure.

[0090] The bitumen-enriched solvent that has flowed downwardly through the
height of the vertical column in either mode can exit the bottom end of
the vertical column, where it can be collected. Any method of collecting
the bitumen-enriched solvent can be used, such as by providing a
collection vessel at the bottom end of the vertical column. The bottom
end of the vertical column can include a metal filter screen having a
mesh size that does not permit first mixture to pass through but which
does allow for bitumen-enriched solvent to pass through and collect in a
collection vessel located under the screen. Collection of
bitumen-enriched solvent can be carried out for any suitable period of
time. In some embodiments, collection is carried out for 2 to 30 minutes.

[0091] Bitumen-enriched solvent that has exited the column can be recycled
back into the top or bottom of the vertical column to perform further
displacement of any bitumen-enriched solvent still contained in the
vertical column. The collection and reintroduction of the
bitumen-enriched solvent into the column can be performed several times
in an attempt to increase the amount of bitumen removed from the column.
Alternatively, or in conjunction with adding bitumen-enriched solvent
into the column, further amounts of fresh first solvent can be added to
the column to displace bitumen-enriched solvent.

[0092] With respect to step 120, a quantity of second solvent is added
into the column in a similar manner as described above with respect to
the addition of the first solvent in order to displace first solvent
entrapped in the column, including the addition of the second solvent
under flooded conditions. The second solvent can be similar or identical
to the second solvent described in greater detail above.

[0093] The quantity of second solvent can be added into the column at the
top end of the column such that the quantity of second solvent flows
downwardly through the first solvent-wet tailings loaded in the column.
As the second solvent flows downwardly, the second solvent displaces
first solvent and eventually forces the first solvent to exit the column
at the bottom end of the column. A mixture of first solvent and second
solvent exiting the column can then be collected.

[0094] As with the bitumen-enriched solvent collected in the previous step
after the addition of first solvent, the mixture of first solvent and
second solvent collected can be reintroduced into the vertical column to
promote further displacement of first solvent from the column. The
collecting and reintroductions step can be performed one or more times.
Alternatively or conjunction with the recycling of the first solvent and
second solvent mixture, additional fresh second solvent can be added to
the column to displace first solvent contained therein.

[0095] In some embodiments, addition of the quantity of second solvent
into the column includes a two-stage addition of the quantity of second
solvent wherein one stage is performed after the first solvent-wet
tailings have been temporarily discharged from the column. The two stage
addition of the quantity of second solvent may be useful when the first
solvent-wet tailings includes a water content (likely originating from
the original bitumen material). This water content can interfere with the
ability of the second solvent to act as a displacement solvent capable of
displacing first solvent out of the column. However, the two stage
addition of the second solvent described herein can overcome this issue.

[0096] In a first stage addition, the first solvent-wet tailings is first
discharged from the column. Any manner of discharging the first
solvent-wet tailings from the column can be used. In some embodiments,
the screen, plug, or valve blocking the bottom end of the vertically
oriented column is removed to allow the first solvent-wet tailings to
pass out of the bottom end of the column.

[0097] After discharging the first solvent-wet tailings from the column, a
first portion of the quantity of second solvent is added to the first
solvent wet tailings. Any manner of adding the first portion of the
quantity of second solvent to the first solvent-wet tailings can be used,
such as by pouring the first portion of the quantity of second solvent
over the first solvent-wet tailings. In some embodiments, the first
solvent-wet tailings is discharged from the column into a vessel that is
capable of containing both the first solvent-wet tailings and the first
portion of the quantity of the second solvent.

[0098] The first portion of the quantity of the second solvent can be any
percentage of the quantity of the second solvent. In some embodiments,
the first portion of the quantity of the second solvent is from 25% to
50% of the total quantity of the second solvent.

[0099] The addition of the first portion of the quantity of the second
solvent to the first solvent-wet tailings results in the first
solvent-wet tailings temporarily becoming first/second solvent-wet
tailings and the formation of a liquid component. The liquid component
can generally includes first solvent, second solvent, water, and
dissolved bitumen. However, the liquid component preferably does not
include solid particles of the tailings, such as silica and clay.

[0100] Liquid component can be separated from the first/second solvent-wet
tailings. Any manner of separating liquid component from the first/second
solvent-wet tailings can be used, such as by decanting liquid component
from the vessel used to hold the first/second solvent-wet tailings and
the first portion of the quantity of the second solvent. Any amount of
the liquid component can be separated, and preferably most or all of the
liquid component is separated.

[0101] Once a portion or all of the liquid component is separated from the
first/second solvent wet tailings, the first/second solvent-wet tailings
are loaded back into the column. The manner of loading the first/second
solvent-wet tailings back into the column can be similar or identical to
the manner in which the first mixture is loaded into the column as
described in greater detail above.

[0102] After the first/second solvent-wet tailings are loaded back into
the column, the second portion of the quantity of the second solvent is
added into the column to displace first solvent from the column. This
addition of the second portion of the quantity of second solvent can be
as described in greater detail above. In some embodiments, the second
portion of the quantity of second solvent is from about 50% to about 75%
of the quantity of second solvent used in step 120. As described in
greater detail above, the addition of the second solvent drives out most
or all of the first solvent and therefore results in the first
solvent-wet tailings (or the first/second solvent wet tailings) becoming
second solvent-wet tailings.

[0103] With respect to step 130, water is added into the column in the
same manner as described above with respect to the addition of the first
solvent and the second solvent into the column. The addition of water
serves to displace the second solvent from the vertical column. Mixtures
of water and second solvent can be collected and reintroduced into the
column to displace further second solvent from the column. Alternatively
or in conjunction with adding the water and second solvent mixture back
into the column, additional water can be added to the column to displace
further second solvent from the column.

[0104] As with step 120, step 130 can be carried out in two steps, with
one step occurring after the second solvent-wet tailings have been
discharged from the column. Each of the steps in adding the quantity of
water to the second solvent-wet tailings may proceed as outlined above
with respect to the two stage addition of second solvent to the first
solvent-wet tailings, including the discharging of the second solvent-wet
tailings from the column, the addition of the first portion of the
quantity of water to the second solvent-wet tailings, the separation of
the liquid component from the second solvent/water-wet tailings, the
re-loading of the second solvent/water-wet tailings into the column, and
the addition of the second portion of the first quantity of water to the
second solvent/water-wet tailings loaded in the column. Furthermore, the
first portion and second portion of the quantity of water can be divided
in a similar or identical manner to the first portion and second portion
of the quantity of second solvent (i.e., 25% to 50% for the first portion
and 50% to 75% for the second portion).

[0105] The material contained in the vertical column after the removal of
second solvent generally includes solvent-dry stackable tails as
described in greater detail above. The solvent-dry, stackable tails can
be removed from the vertical column by any suitable process. The
solvent-dry, stackable tailings can be removed from either the top end or
the bottom end of the vertical column. In some embodiments, the bottom
end of the vertical column is covered with one or more removable plug or
valve, and the one or more plug or valve can be removed to allow the
solvent-dry, stackable tailings to discharge out of the vertical column
by the force of gravity. For example, if the bottom end of the vertical
column is blocked by a screen as described in greater detail above, the
screen can be removed to allow the solvent-dry, stackable tailings to
flow out of the vertical column. Alternatively, the screen may be an
annular ring at the lower part of the column to allow dissolved bitumen
or liquids to pass without obstructing the outflow of solids once the
plug or valve is removed. In certain embodiments, the vertical column is
lifted off of the ground, thereby allowing the solvent-dry, stackable
tailings to flow out of the bottom end of the vertical column. External
forces can also be applied to the vertical column to promote the
discharging of the solvent-dry, stackable tailings from the vertical
column.

[0106] In some embodiments, any of the solvents or water added into the
column can be added into the column from the bottom of the column to
create an upflow of solvent or water into the column. Solvents or water
can be added in this manner to unplug a vertical column that has become
plugged. The bottom of the column may be closed off to force the solvent
or water upwards when introduced at the bottom of the column. For
example, increasing the flow rate and pressure of the injected solvent or
water can result in closing off the bottom of the column. The upwardly
moving solvent or water can then displace or dissolve the material
causing the plug in the column.

[0107] With reference to FIG. 2, a system 200 for carrying out the
above-described method. includes a mixer 205 for mixing bitumen material
210 and first solvent 215. Any suitable mixing vessel can be used,
including a mixing vessel that operates under pressure in order to
maintain the first solvent 215 as a liquid. A first mixture 220 is formed
by the mixing of the bitumen material 210 and the first solvent 215 in
the mixer 205. The first mixture 220 is transported to a first separation
unit 225 where bitumen-enriched solvent 230 is separated from the first
mixture 220. Any separation unit suitable for separating the
bitumen-enriched solvent 230 from the first mixture 220 can be used. Gas
285-1 can be pumped into the first separation unit 225 to promote
separation of bitumen from the non-bitumen components of the bitumen
material. When gas 285-1 is pumped into first separation unit 225, the
spent gas may also exit the first separation unit 225 with the
bitumen-enriched solvent 230. Because the gas does not dissolve in either
the bitumen or the first solvent of the first mixture 220, the gas exits
with the bitumen-enriched solvent 230 and does not require any additional
separation processing (but may be recovered and reused from an economics
standpoint). Removal of the bitumen-enriched solvent 230 from the first
mixture 220 via first separation unit 225 results in the first mixture
220 becoming first solvent-wet tailings 235. The first solvent-wet
tailings 235 produced by the first separation unit 225 are transported to
a second separation unit 240 where second solvent 245 is added to the
first solvent-wet tailings 235 in order to separate first solvent 255
from the first solvent-wet tailings 235. Any separation unit suitable for
separating the first solvent 255 from the first solvent wet tailings 235
may be used. Gas 285-2 may be pumped into the second separation unit 240
to promote separation of the first solvent 255 from the non-bitumen
components of the first solvent-wet tailings 235. When gas 285-2 is
pumped into second separation unit 240, the spent gas may also exit the
second separation unit 240 with the first solvent 255. Because the gas
does not dissolve in the first solvent 255, the gas exits without need
for any additional separation processing, but may be recovered and reused
from an economics standpoint. Separation of the first solvent 255 from
the first solvent-wet tailings 235 results in the first solvent-wet
tailings 235 becoming second solvent-wet tailings 250. The second
solvent-wet tailings 250 are transported to a third separation unit 260
where the second solvent 265 is removed from the second solvent-wet
tailings 250 by adding water 270 to the second solvent-wet tailings 250.
Any separation unit suitable for separating the second solvent 265 from
the second solvent wet tailings 250 may be used. Separation of the second
solvent 265 from the second solvent-wet tailings 250 results in the
second solvent-wet tailings 250 becoming solvent-dry, stackable tailings
275.

[0108] With reference to FIG. 3, a system 300 for carrying out the
extraction method disclosed herein that utilizes a vertical column
includes a mixing vessel 305 for mixing bitumen material 310 with a first
quantity of first solvent 315 to form a first mixture 320. Any type of
mixing vessel may be used to mix the bitumen material 310 and the first
solvent 315.

[0109] The first mixture 320 is then loaded in the vertical column 325.
FIG. 3 depicts the first mixture 320 being loaded in the top end of the
vertical column 325, but the first mixture 320 can also be loaded from
the bottom end of the vertical column 325 or from the side of the
vertical column 325. Once the first mixture 320 is loaded in the vertical
column 325, a second quantity of first solvent 330 is injected into the
top end of the vertical column. The second quantity of first solvent 330
flows down the height of the vertical column 325, dissolving solid
bitumen in the first mixture 320 and/or displacing dissolved bitumen in
the first mixture 320 along the way. The non-bitumen components of the
bitumen material remain in a packed condition in the vertical column 325
as the second quantity of first solvent 330 passes through the first
mixture 320. The second quantity of first solvent 330 exits the bottom
end of the vertical column 325 as a bitumen-enriched solvent phase 335.
The second quantity of first solvent 330 is now a bitumen-enriched
solvent phase 335 because the second quantity of first solvent 330
dissolves solid bitumen contained in the first mixture 320 and/or
coalesces with dissolved bitumen contained in the first mixture 320 as
the second quantity of first solvent 330 passed through the vertical
column 325.

[0110] The bitumen-enriched solvent phase 335 is collected at the bottom
end of the vertical column 325 for further processing of the bitumen
contained therein. Some of the second quantity of first solvent 330
remains in the first mixture 320 loaded in the vertical column 325. A
quantity of second solvent 340 is then added to the vertical column 325.
The quantity of second solvent 340 flows down the height of the vertical
column 325, dissolving and/or displacing first solvent contained in the
first mixture 320. The quantity of second solvent 340 exits the bottom
end of the vertical column 325 as a first solvent-second solvent mixture
345.

[0111] The first solvent-solvent mixture 345 is collected at the bottom
end of the vertical column 325 to recover and possibly reuse the first
and second solvents contained therein.

[0112] A portion of the second solvent added into the vertical column 325
remains behind in the mixture loaded in the vertical column 325. Water
350 is added to the vertical column 325 to displace second solvent out of
the vertical column 325. The water 350 flows down the height of the
vertical column 325, displacing second solvent contained in the'first
mixture 320. The water 350 exits the bottom end of the vertical column
325 as a water and second solvent mixture 355, which can be separated
into water and second solvent so each component may be reused.

[0113] Optionally, the system also includes one or more gas purge
injections 365-1, 365-2, and 365-3. The gas purge injections 365-1,
365-2, and 365-3 may occur before and/or after any of the solvent or
water injection steps, and may serve to help separate bitumen, first
solvent, and second solvent from the non-bitumen component of the first
mixture 320.

[0114] After displacement of second solvent, the material loaded in the
column 325 is solvent-dry, stackable tailings 360. The solvent-dry,
stackable tailings 360 is discharged out of the vertical column 325. FIG.
3 depicts solvent-dry, stackable tailings 360 being removed from the
bottom end of the vertical column 325, but the solvent-dry, stackable
tailings 360 may also be discharged from the top end of the vertical
column 325.

[0115] With reference to FIG. 4, a system for carrying out the extraction
method disclosed herein that utilizes countercurrent washing includes
loading a first mixture 410 of bitumen material and first solvent in a
washing unit 405. The washing unit 405 receives the first mixture 410 and
transports it in a first direction while moving first solvent 415 towards
the first mixture 410 in a direction opposite the direction the first
mixture 410 is traveling. The first mixture 410 mixes with the first
solvent 415, during which bitumen-enriched solvent in the first mixture
410 is displaced from the first mixture 410 by the first solvent 415.
Bitumen-enriched solvent 420 and first solvent-wet tailings 425 separate
due to the countercurrent configuration of the washing unit 405.

[0116] First solvent-wet tailings 425 are transported to a second washing
unit 430 where it flows in a direction opposite to a direction of flow of
second solvent 435 introduced into the second washing unit 430. The first
solvent-wet tailings 425 mix with the second solvent 435, during which
the first solvent in the first solvent-wet tailings 425 is displaced by
the second solvent 435. Accordingly, first solvent-second solvent mixture
440 and second solvent-wet tailings 445 are formed. The first
solvent-second solvent mixture 440 and the second solvent-wet tailings
445 separate due to the countercurrent configuration of the second
washing unit 430.

[0117] Second solvent-wet tailings 445 are transported to third washing
unit 450 where it flows in a direction opposite to a direction of flow of
water 455 introduced into the second washing unit 450. The second
solvent-wet tailings 445 mix with the water 455, during which the second
solvent in the second solvent-wet tailings 445 is displaced by the water
455. Accordingly, second solvent-water mixture 460 and solvent-dry,
stackable tailings 465 are formed. The second solvent-water mixture 460
and the solvent-dry, stackable tailings 465 separate due to the
countercurrent configuration of the third washing unit 450. The final
stage 450 may be a column, vessel, or plate and frame filter as described
previously to effect a more efficient final water removal to produce
solvent-dry stackable tailings.

[0118] In any of the embodiments described herein, the method can include
a further step of depositing the solvent-dry, stackable tailings in a
mine pit formed when mining the first bitumen material. The manner in
which the solvent-dry, stackable tailings are deposited in the mine pit
is not limited. In one example, the solvent-dry, stackable tailings is
transported to the mine pit by one or more trucks and poured into the
mine pit from the trucks. Solvent-dry, stackable tailings may also be
deposited in a mine pit through the use of conveyor belts that empty into
the mine pits. In some embodiments, the volume of solvent-dry, stackable
tailings produced from the mined bitumen material is less than the
original amount of bitumen material mined such that the entirety of the
solvent-dry, stackable tailings may be deposited in the mine pit. To the
contrary, conventional hot water processing of bitumen material generally
produce wet tailings having a volume that is 125% of the original volume
of the mined bitumen material, even after settling and decanting of
excess liquid. Additionally, the presence of some amount of water in the
solvent-dry, stackable tailings may aid in the compaction of the
solvent-dry, stackable tailings. This can lead to a much earlier
trafficable reclamation for the deposit, an aspect of tailings management
which has not been attained by tar sands operators to date.

[0119] As described in greater detail in co-pending U.S. application Ser.
Nos. 12/041,554 and 11/249,234, further processing can be performed on
other components produced by the methods described above. For example,
the bitumen-enriched solvent phase can be processed to separate the
bitumen therefrom. Furthermore, as described in co-pending application
Ser. No. 12/509,298, herein incorporated by reference, any bitumen
obtained from the above-described methods or from further processing of
the bitumen-enriched solvent phases produced by the above-described
processes can be cracked in a nozzle reactor (with or without
deasphalting) to produce light hydrocarbon distillate. The light
hydrocarbon distillate can then be used as a first solvent to extract
bitumen from bitumen material. In one example, the light hydrocarbon
distillate produced is recycled within the same process to initiate
extraction of bitumen from further bitumen material. Additionally, any
solvent separated or removed from a mixture can be recovered and reused
in the process. For example, the first solvent-enriched second solvent
phase can be recovered after being separated from the second solvent-wet
tailings and reused in the process. More specifically, the first
solvent-enriched second solvent phase is separated into first and second
solvent that may be used in the process. Separation of the solvents may
be accomplished by any know method, such as through the use of stills.

[0120] In some embodiments, tailings produced by a bitumen extraction
process are treated with water to remove paraffinic solvent contained in
the tailings. The paraffinic solvent can be present in the tailings as a
result of using paraffinic solvent to wash a solvent from the tailings
that was previously used to dissolve and remove bitumen from bituminous
material. The water effectively removes paraffinic solvent from the
tailings at least in part because of the immiscibility of the water and
paraffinic solvent. For example, when tailings are treated with water by
passing a plug of water through the tailings, the immiscibility of the
water and paraffinic solvent helps to ensure that the water pushes the
paraffinic solvent out of the tailings rather than mix with the
paraffinic solvent and potentially leave a mixture of paraffinic solvent
and water in the tailings.

[0121] In some embodiments, a method of performing bitumen extraction on
bituminous material that includes the formation of solvent-dry tailings
includes a step 500 of passing a first solvent through a first quantity
of bituminous material, a step 510 of passing a second solvent through
the first quantity of bituminous material, and a step of 520 of passing
water through, the first quantity of bituminous material. In this method,
the second solvent is a paraffinic solvent.

[0122] In step 500, first solvent is passed through a first quantity of
bituminous material. One aim of step 500 is to dissolve bitumen contained
in the bituminous material into the first solvent as a means for
eventually extracting the bitumen content from the bituminous material.
The first solvent typically passes through the bituminous material by
traveling through the interstitial spaces within the bituminous material.
As it passes through these spaces, the first solvent contacts bitumen
contained in the bituminous material and dissolves the bitumen. The
solvent thus becomes "bitumen-enriched," and when the bitumen-enriched
solvent has passed all the way through the bituminous material, bitumen
content in the bituminous material has been effectively extracted from
the bituminous material.

[0123] The bituminous material can be similar or identical to the bitumen
material described in greater detail above. In some embodiments, the
bituminous material is oil sand or tar sand. In some embodiments, the
bituminous material is obtained from previous bitumen extraction process
steps. For example, in some embodiments, oil sand or the like is mixed
with solvent capable of dissolving bitumen (e.g., aromatic solvents such
as those discussed in greater detail above), and the resulting mixture is
separated into a bitumen-enriched solvent phase and a bitumen-depleted
tailings phase. The mixing can be carried out in a mixing drum or the
like, and the separation can be carried out using a thickener,
hydrocyclone, or the like. The bitumen-enriched solvent phase can be
subjected to further processing that separates the solvent from the
bitumen. Separated solvent can be reused in the process and bitumen can
be subjected to upgrading processes. The bitumen-depleted tailings phase
from such a process will typically include a solvent content and a
bitumen content in addition to the sand and clay of the original oil
sand. For example, in some embodiments, the bitumen-depleted tailings
phase includes up to 40% of the bitumen contained in the original oil
sand. This bitumen-depleted tailings can serve as the bituminous material
used in the method described herein.

[0124] Any technique that results in the passing of first solvent through
the bituminous material can be used. In some embodiments, the first
solvent is passed through the bituminous material by loading the
bituminous material in a vessel, adding solvent at one end of the vessel,
and causing the solvent to move through the bituminous material to the
opposite end of the vessel. Any vessel capable of containing the
bituminous material can be used, and the size and shape of the vessel is
not limited. Solvent can be moved through the bituminous material using,
for example, gravity or an external force, such as the application of an
inert gas at one end of the vessel. When inert gas is used to move
solvent through the bituminous material, the vessel can be a sealed
vessel, so that the introduction of inert gas into one end of the vessel
forces the solvent to move through the bituminous material to the other
end of the vessel.

[0125] In some embodiments, the vessel or sealed vessel is a vertical
column as described in greater detail above. The bituminous material is
loaded in the vertical column as described above, and solvent is added to
the top end of the vessel such that it may move downwardly through the
bituminous material loaded in the vertical column to the bottom end of
the vessel. As mentioned above, gravity can be relied on to move the
solvent down through the bituminous material, or the vertical column can
be a sealed vertical column and inert gas can be introduced at the top
end of the vertical column after solvent has been added into the column
to force the solvent to move downwardly through the bituminous material
loaded in the vertical column. When inert gas is used to promote the
movement of the solvent through the bituminous material, the inert gas
can be applied at a pressure ranging from 30 psig to 300 psig. Typically,
the pressure at which the inert gas is applied into vertical column can
vary based on how packed the bituminous material is in the vertical
column, the height of the column, and the resulting pressure drop over
the column length. The more packed the bituminous material, the greater
the pressure will need to be to move the solvent downwardly through the
bituminous material. Any suitable inert gas can be used, and in some
embodiments, the inert gas is nitrogen.

[0126] The first solvent used in step 500 can be similar or identical to
the first solvent described in greater detail above. The first solvent is
preferably a solvent capable of dissolving bitumen, and can be an
aromatic solvent, such benzene, toluene, xylene, aromatic alcohols,
kerosene, diesel (including biodiesel), light gas oil, light distillate
(distillate having boiling point temperature in the range of from
140° C. to 260° C.), commercial aromatic solvents such as
Aromatic 100, Aromatic 150, and Aromatic 200, and/or naphtha.

[0127] The amount of solvent passed through the bituminous material in
step 500 typically depends on the bitumen content of the bituminous
material, although other factors can impact how much solvent is passed
through the bituminous material. In some embodiments, a ratio of solvent
to bitumen content of the bituminous material on a volume basis (or S:B
ratio) is used to specify the amount of solvent passes through the
bituminous material. The S:B ratio in step 500 can vary from between
0.5:1 to 3:1.

[0128] The first solvent that passes through the bituminous material will
have a bitumen content based on the amount of bitumen that dissolves into
the first solvent as it passes through the bituminous material. In some
embodiments, the first solvent will have removed from 40% to 75% of the
bitumen content of the bituminous material. The first solvent that passes
through the bituminous material can therefore be collected and subjected
to further processing that separates the solvent from the bitumen
content. The separated solvent can be reused in the process, and the
bitumen can be subjected to upgrading processes to produce lighter
hydrocarbons.

[0129] In some embodiments, a portion of the first solvent that is
introduced into the bituminous material will not pass all the way through
the bituminous material, and will instead remain in the interstitial
pores of the bituminous material. This trapped first solvent can still
have dissolved bitumen therein, and therefore step 510 of passing second
solvent through the bituminous material can be carried out in order to
displace the trapped first solvent out of the bituminous material.

[0130] Step 510 can be similar or identical to step 500 described above,
with the exception of using a second solvent in place of a first solvent.
In embodiments where the bituminous material is loaded in a vessel, such
as a sealed vertical column, the second solvent can be added at the top
end of the vertical column and allowed to move down through the
bituminous material either via the force of gravity or by applying an
external force, such as the addition of inert gas into the vertical
column following the addition of second solvent. The second solvent
passes through the bituminous material, and in so doing, displaces the
first, solvent trapped in the bituminous material and moves the trapped
first solvent through the bituminous material. Eventually, a mixture of
second solvent and previously trapped first solvent will pass out of the
bituminous material.

[0131] Any second solvent capable of displacing the first solvent can be
used in step 510. It is also preferable that the second solvent used be
capable of dissolving bitumen and that the second solvent is miscible
with the first solvent so that the second solvent moving through the
bituminous material both forces the trapped first solvent out of the
bituminous material and dissolves any bitumen contained in the bituminous
material that was not dissolved by the first solvent. In some
embodiments, the second solvent is a paraffinic solvent, such as ethane,
butane, pentane, hexane and heptane. Paraffinic solvents are useful as
second solvents because they are capable of both displacing and diluting
first solvent and dissolving bitumen, and, as discussed in greater detail
below, are immiscible with water and can therefore be readily removed
from the bituminous material via a water wash.

[0132] As with the first solvent, the amount of second solvent passed
through the bituminous material can depend on factors such as the bitumen
content of the bituminous material. In some embodiments, the ratio of
volume of second solvent added to the bituminous material to the original
bitumen volume in the bituminous material is from 0.5:1 to 3:1.

[0133] A portion of the second solvent introduced into the bituminous
material will pass through the entirety of the bituminous material, and
can be collected as it leaves the bituminous material. The second solvent
that leaves the bituminous material will include first solvent that was
previously trapped in the bituminous material and some dissolved bitumen.
In some embodiments, 99% of the first solvent trapped in the bituminous
materials will be removed by the second solvent (in one or multiple
washes of second solvent), meaning that after the second solvent is
passed through the bituminous material, the bituminous material may
contain less than 200 ppm of first solvent. Additionally, the second
solvent passing through the bituminous material may dissolve a majority
of the bitumen that remained undissolved in the bituminous material after
passing the first solvent through the bituminous material. In some
embodiments, the bituminous material contains less than 1wt % of the
bitumen content present in the original bituminous material. The mixture
of second solvent, first solvent, and dissolved bitumen that exits the
bituminous material can be collected and treated to separate the three
components. The recovered first and second solvents can be reused in the
process, and the bitumen can be subjected to upgrading.

[0134] A portion of the second solvent introduced into the bituminous
material will become trapped in the interstitial pores of the bituminous
material. For example, 40% of the second solvent introduced into the
bituminous material can become trapped in the bituminous material. In
some embodiments, this second solvent can have some bitumen dissolved
therein, and it can therefore be useful to take steps to try and remove
this second solvent from the bituminous material.

[0135] In step 520, water is passed through the bituminous material having
second solvent trapped therein in an effort to move the second solvent
out of the bituminous material. As noted above, the water is effective at
displacing the paraffinic second solvent from the bituminous material due
to the immiscibility of the paraffinic second solvent and the water. For
example, when a plug of water is moved through the bituminous material,
the paraffinic solvent is pushed out of the paraffinic solvent by the
water plug rather than mixing with the water, which could possibly lead
to paraffinic solvent remaining in the bituminous material.

[0136] Passing water through the bituminous material can be carried out in
a similar or identical fashion to how the first solvent and second
solvent are passed through the bituminous material. While any manner of
passing the water through the bituminous material can be used, some
embodiments call for the water to be passed through bituminous material
loaded in a vessel, such as a sealed vertical column. In such
embodiments, water is introduced at the top end of the sealed vertical
column, and moves downwardly through the bituminous material under the
force of gravity or through the application of external force. In some
embodiments, inert gas is introduced into the top end of the sealed
vertical column after water has been introduced into the top end of the
sealed vertical column to push the water downward through the bituminous
material. When inert gas is introduced, the inert gas can be introduced
at a pressure of from 30 to 50 psig. In some embodiments, the pressure of
the inert gas is kept relatively low so as not to move the water through
the bituminous material at a velocity that results in disrupting the
clays attached to the sand particles in the bituminous material.

[0137] The amount of water used in step 520 can be based on a ratio of
volume of water added to the total volume of the interstitial pore spaces
in the bituminous material (W:P ratio). In some embodiments, the W:P
ratio for step 520 is from 1:1 to 5:1, meaning that, generally speaking,
a volume of water anywhere from one to five times the volume of pore
spaces in the bituminous material is passed through the bituminous
material.

[0138] The water passing through the bituminous material in step 520 will
result in second solvent and water exiting the bituminous material. The
second solvent can include dissolved bitumen, and therefore steps can be
taken to separate the water, second solvent, and bitumen. Generally
speaking, the water and second solvent (having bitumen dissolved therein)
is relatively easy to separate due to the immiscibility of the second
solvent in the water. In some embodiments, the second solvent and water
may naturally phase separate, forming a layer of solvent over the water.
Once the solvent and water are separated, the second solvent can be
processed to separate the solvent from the bitumen. Separated water and
solvent can be reused in the process, and bitumen can be subjected to
upgrading processing.

[0139] Any of the above described steps wherein first solvent, second
solvent, or water is passed through the bituminous material can be
performed in multiple stages. That is to say, multiple quantities of
first solvent can be passed through the bituminous material in individual
stages prior to passing any second solvent through the bituminous
material. Similarly, multiple quantities of second solvent can be passed
through the bituminous material in individual stages prior to passing
water through the bituminous material. And finally, multiple quantities
of water can be passed through the bituminous material in individual
stages after the second solvent wash has been completed. Using multiple
stages of washes for one or more of the first solvent, second solvent,
and water can result in more complete removal of bitumen, first solvent,
and second solvent from the bituminous material.

[0140] After steps 500, 510, and 520 have been carried out, a tailings
phase is left over. When a vessel is used to carry out these steps, the
tailings Scan be discharged from the vessel. The tailings phase generally
includes the non-bitumen solid materials of the original bituminous
material, such as sand and clay. In conventional bitumen extraction
processes that utilize solvents, the tailings include a solvent content.
However, in the above method, the second solvent and water washes can
result in the production of tailings that have less than 200 ppm first
solvent and less than 100 ppm second solvent. Additionally, the tailings
can include less than 2 wt % of the original bitumen content of the
bituminous material. Bitumen and solvent levels in these ranges can
satisfy stringent environmental regulations set by various organizations
overseeing oil sand mining and bitumen extraction.

[0141] The tailings can also include a water content due to the water
content present in the original bituminous material and the water added
to the bituminous material as part of removing second solvent from the
bituminous material. In some embodiments, the water content of the
tailings is about 14 wt % and the tailings can be transported by conveyor
for deposition. In some embodiments, it may be useful to add additional
water to the discharged tailings so that the tailings are in the form of
a pumpable slurry.

[0142] In some embodiments, a method of extracting bitumen from bituminous
material and producing solvent-dry tailings includes a step 600 of
contacting a bituminous material with a first solvent and forming a first
solvent-wet bituminous material, a step 610 of contacting the first
solvent-wet bituminous material with a second solvent and forming a
second solvent-wet bituminous material, and a step 620 of contacting the
second solvent-wet bituminous material with water and forming a water-wet
bituminous material. In the method described above, the second solvent is
preferably a paraffinic solvent.

[0143] The first solvent, second solvent, water, and bituminous material
used in steps 600, 610, and 620 are similar or identical to the first
solvent, second solvent, and water described above in the method
including steps 500, 510, and 520.

[0144] Any or all of the contacting steps 600, 610, and 620 can include
passing the first solvent, second solvent, and water through the
bituminous material as described in greater detail above. When a
contacting step 600, 610, or 620 includes passing one of the wash
materials through the bituminous material, the bituminous material
becomes wet with whichever of the wash materials is passed through the
bituminous material. For example, when bituminous material is contacted
with first solvent by passing the first solvent through the bituminous
material, a portion of the first solvent becomes trapped in the
bituminous material, thereby making the bituminous material first
solvent-wet bituminous material. When each of steps 600, 610, and 620
include passing the wash material through the bituminous material, the
method is similar or identical to the method described above (i.e., the
method including steps 500, 510, and 520).

[0145] Any or all of the contacting step 600, 610, and 620 can also
include adding wash material to bituminous material and mixing the two
components into a mixture or slurry. Mixing can differ from passing a
wash material through the bituminous material in that a mixing step does
not require the movement of wash material from one side of the bituminous
material through to the opposite side of the bituminous material and the
discharge of a relatively large portion of the wash material from the
bituminous material. Rather, mixing generally includes a majority or all
of the wash material remaining with the bituminous material in the form
of a slurry and the two components being mixed together.

[0146] Any suitable manner of mixing first solvent, second solvent, or
water with the bituminous material can be used to carry out step 600,
610, or 620. The mixing can occur by adding both the bituminous material
and the wash material to a vessel and mixing the two components together
to form a slurry of bituminous material that is wet with the specific
wash material used in the contacting step. Mixing together the wash
material and the bituminous material can provide desirable results. For
example, when first solvent is mixed with bituminous material, the mixing
promotes the dissolution of bitumen from the bituminous material into the
first solvent.

[0147] In embodiments where any of the contacting steps 600, 610, 620
include mixing wash material with the bituminous material, the contacting
step can further include a step of separating out certain components from
the resulting mixture. When step 600 includes mixing, the separation step
will generally include separating a bitumen-enriched first solvent phase
from first solvent-wet bituminous material. When step 610 includes
mixing, the separation step will generally include separating a mixture
of first solvent and second solvent from the second solvent-wet
bituminous material. When step 620 includes mixing, the separation step
will generally include separating a mixture of second solvent and water
from the bituminous material. Any suitable separation methods can be used
to carry out the above-described separations. Exemplary separation
methods can include any of those described in previous embodiments,
including but not limited to, filtering, settling and decanting, gravity
or gas overpressure drainage, and displacement washing.

[0148] In some embodiments, one or more of the separation steps described
above are carried out in a hydrocyclone. Generally speaking, the mixture
formed in step 600, 610, or 620 is transported into a hydrocyclone where
the hydrocyclone acts to separate the mixture into an overflow and an
underflow. When the mixture formed in step 600 is separated in a
hydrocyclone, the mixture will be separated into a bitumen-enriched first
solvent overflow and a first solvent-wet bituminous material underflow.
When the mixture formed in step 610 is separated in a hydrocyclone, the
mixture will be separated into a first solvent and second solvent mixture
overflow and a second solvent-wet bituminous material underflow. When the
mixture formed in step 620 is separated in a hydrocyclone, the mixture
will be separated into a second solvent and water mixture overflow and a
water-wet bituminous material underflow.

[0149] Any suitable hydrocyclone can be used to carry out the separation
process. Typical hydrocyclones suitable for use in the above described
method include hydrocyclone separators that utilize centrifugal forces to
separate materials of different density, size, and/or shape. The
hydrocyclone will typically include a stationary vessel having an upper
cylindrical section narrowing to form a conical base. The mixtures are
introduced into the hydrocyclone at a direction generally perpendicular
to the axis of the hydrocyclone. This induces a spiral rotation on the
mixture inside the hydrocyclone and enhances the radial acceleration on
the solids within the mixture. The hydrocyclone also typically includes
two outlets. The underflow outlet is situated at the apex of the cone,
and the overflow outlet is an axial tube rising to the vessel top
(sometimes also called the vortex finder).

[0150] When the density of the solids is greater than that of the fluid
portion of the mixture, the heavier solid particles migrate quickly
towards the cone wall where the flow is directed downwards. Lower density
solid particles migrate more slowly and therefore may be captured in the
upward spiral flow and exit from vortex finder via the low pressure
center. Factors affecting the separation efficiency include fluid
velocity, density, and viscosity, as well as the mass, size, and density
of the tailings particles. The geometric configuration of the
hydrocyclone can also play a role in separation efficiency. Parameters
that can be varied to adjust separation efficiency include cyclone
diameter, inlet width and height, overflow diameter, position of the
vortex finder, height of the cylindrical chamber, total height of the
hydrocyclone, and underflow diameter.

[0151] A separate hydrocyclone can be provided to carry out each of the
separation steps that occur after the contacting (i.e., mixing) steps
600, 610, 620, or a single hydrocyclone can be used for one or more
separations. In embodiments, where a separate hydrocyclone is provided
for each separation, a first hydrocyclone receives and separates the
first mixture formed in step 600, a second hydrocyclone receives and
separates the second mixture formed in step 610, and a third hydrocyclone
receives and separates the third mixture formed in step 620. Each of the
hydrocyclones can be sized and configured especially for the separation
for which it is used. When each separation step is carried out in a
separate hydrocyclone, the process can generally proceed as follows. A
bituminous material and a first solvent are contacted so as to form a
first mixture. The first mixture is delivered into the first hydrocyclone
and separated into a bitumen-enriched first solvent overflow and a first
solvent-wet bituminous material underflow. The underflow is contacted
with second solvent so as to form a second mixture. The second mixture is
delivered into the second hydrocyclone and separated into a
bitumen-enriched second solvent overflow and a second solvent-wet
bituminous material underflow. The underflow is contacted with water so
as to form a third mixture. The third mixture is delivered into the third
hydrocyclone and separated into a mixture of first solvent and second
solvent overflow and a water-wet bituminous material underflow.

[0152] As noted above, each separation step does not require its own
hydrocylone. In some embodiments, each separation step can be carried out
in the same hydrocyclone. Alternatively, two separation steps can take
place in one hydrocyclone and a second hydrocyclone can be provided for
the third separation step. Thus, for example, a first hydrocyclone can
separate the first mixture into a bitumen-enriched first solvent overflow
and a first solvent-wet bituminous material underflow, the underflow can
be contacted with second solvent so as to form a second mixture, and the
second mixture can be delivered into the same hydrocyclone to separate
the second mixture into a bitumen-enriched second solvent overflow and a
second solvent-wet bituminous material underflow. A third hydrocyclone
can then be used to separate the third mixture formed from the mixture of
second solvent-wet bituminous material and water.

[0153] In some embodiments, each separation step can include multiple
stages such that the mixture is passed through the hydrocyclone multiple
times before being passed through to the next hydrocyclone. For example,
the first mixture of bituminous material and first solvent can be passed
through a hydrocyclone a first time, followed by collecting the first
solvent-wet bituminous material overflow, adding an additional quantity
of first solvent, and passing the resulting mixture through the same
hydrocyclone. This can be repeated numerous times to increase the
separation efficiency. In the case of the third separation step, multiple
passes through the hydrocyclone may be necessary to effect a suitable
separation of second solvent from the water-wet bituminous material
because of the immiscibility between the second solvent (i.e. paraffinic
solvent) and the water.

[0154] When solvent is added to a stream separated by the hydrocyclone,
such as in the case of adding additional first solvent to the
first-solvent wet bituminous material overflow described above, the
additional solvent can be obtained from a downstream hydrocyclone
separation. In this manner, the solvent flows counter current to the
solids for multiple washes and more efficient bitumen extraction with
higher bitumen loading into the solvent is obtained with each subsequent
hydrocyclone stage.

[0155] Any bitumen recovered from the above-described methods, such as the
bitumen content of the bitumen-enriched solvent phases, can also undergo
any type of upgrading processing known to those of ordinary skill in the
art. Upgrading of the bitumen can comprise any processing that generally
produces a stable liquid (i.e., synthetic crude oil) and any subsequent
refinement of synthetic crude oil into petroleum products. The process of
upgrading bitumen to synthetic crude oil can include any processes known
to those of ordinary skill in the art, such as heating or cracking the
bitumen to produce synthetic crude. The process of refining synthetic
crude can also include any processes known to those of ordinary skill in
the art, such as distillation, hydrocracking, hydrotreating, and coking.
The petroleum products produced by the upgrading process are not limited,
any may include petroleum, diesel fuel, asphalt base, heating oil,
kerosene, and liquefied petroleum gas.

[0156] A first bitumen extraction experiment was conducted using a filter
press 21.1 kg of oil sand ore having a bitumen content of 13.5 wt % was
mixed with 5.9 kg of disbit solvent containing 1.4 kg of bitumen and 4.5
kg of Aromatic 150. The disbit solvent to bitumen ratio was about 1:2.1.
The disbit solvent and oil sand ore were mixed for 10 minutes in a
disaggregation device.

[0157] The ore/solvent mixture was removed from the disaggregation device
and pumped to the filter press. The filter press was filled through a
fill orifice until pressure reached a maximum. The filter press was
pressurized with an inert gas and the bitumen-enriched solvent phase
collected at the outlet of the filter press. The bitumen-enriched solvent
phase weighed 5.4 kg, including 2.6 kg of bitumen and 2.8 kg of disbit
solvent. Disbit-wet tailings remained in the filter press. The bitumen
recovery for this initial step amounted to 62%.

[0158] A fresh solution of Aromatic 150 was pumped into the filter press
at a solvent to original bitumen weight ratio of 1.1:1. The filter press
was pressurized with inert atmosphere and the fresh Aromatic 150 was
forced through the disbit-wet tailings in a plug flow `washing` action.
The secondary bitumen-enriched solvent phase was collected at the outlet
of the plate and frame filter press. The secondary bitumen-enriched
solvent phase weighed 5.8 kg, including 1.2 kg of bitumen and 4.6 kg of
Aromatic 150. The solvent-wet tailings remained in the plate and frame
filter press. The bitumen recovery for this second step amounted to 29%.
The bitumen recovery for the first and second step combined was therefore
95%.

[0159] The solvent-wet tailings remaining in the filter press were cleaned
of residual Aromatic 150 and any remaining bitumen using a secondary
lighter solvent of methanol. The fresh solution of secondary solvent was
pumped into the filter press across the solvent-wet tailings at a
secondary solvent to original bitumen weight ratio of 2.2:1. The filter
press was pressurized with inert atmosphere while 10.1 kg of the Aromatic
150-methanol mixture was collected at the outlet of the filter. The
Aromatic 150-methanol mixture included 0.3 kg of bitumen, 1.8 kg of
Aromatic 150 and 8.0 kg of methanol. The Aromatic 150-methanol mixture
was sent to an evaporation separation process to recycle the secondary
solvent. The second solvent-wet tailings remaining in the filter press
included 0.2 kg bitumen and 8 kg of secondary solvent. The bitumen
recovery of the entire process amounted to 98%.

[0160] Room temperature water was injected into the second solvent-wet
tailings loaded in the filter press to remove the residual secondary
solvent and produce final solvent-dry, stackable tailings. The
solvent-dry, stackable tailings had a total weight of 20.8 kg, including
0.07 kg bitumen, 0.17 kg Aromatic 150, and 0.1 kg secondary solvent.

[0161] Table 1 summarizes the measurements taken of various samples
throughout the experiment.

[0162] A second bitumen extraction experiment was conducted in the same
manner as described above in Example 1, with the exception that a
PneumaPress®-type horizontal pressure filter was used to carry out
the experiment. The results of the second bitumen extraction experiment
are summarized below in Table 2.

Semi-Continuous Countercurrent Washing Using a Vertical Column in Down
Flow Mode

[0163] Two trials of a third bitumen extraction experiment were carried
out in a 3 inch diameter by 3 feet vertical column fitted with flanges on
the top and bottom of the column. The bottom flange had a 1/2'' solvent
outlet port and was covered with a 120 mesh metal screen. The top flange
had a solvent inlet port, pressure relief valve, and nitrogen inlet to
control the pressure applied to the headspace in the column.

[0164] In each trial, Athabasca oil sand ore containing about 14% bitumen
was dry screened to provide pieces of ore having a size of 1/4'' or less.
The ore was forced through the screen leaving only residual clay balls
and rocks behind. The screened ore was disaggregated with recycled
secondary disbit (Aromatic 150 and bitumen) in a Lightning Lab Master
Mixer using the A320 down pumping blade.

[0165] The slurry produced from the disaggregation step was loaded into
the column by hand. After the slurry was loaded in the column, an initial
nitrogen purge was used to drive out an initial quantity of disbit.
Primary wash solvent of Aromatic 150 was then pumped into the top of the
column, followed by a second nitrogen purge to displace the wash solvent.
A secondary wash solvent of methanol was added to the top of the column
followed by a third nitrogen purge.

[0166] The final wash consisted of adding room temperature water to the
column followed by a final nitrogen purge. The nitrogen pressure was held
constant at a pressure of 20 psig. Samples were taken of the first three
products and analyzed for Aromatic 150, methanol, and bitumen content,
where applicable. The tailings were dried in an oven at 100° C. to
drive off residual moisture/solvent and analyzed for recoverable bitumen
content in a Dean-Stark apparatus.

[0167] The mass balances for the two trials are shown in the Tables 3 and
4 below. While it is noted that the methanol recoveries are relatively
low, this can likely be attributed to the greater than 100% recovery in
the water wash processing step, as some methanol is co-recovered by the
water wash.

Semi-Continuous Countercurrent Washing Using a Vertical Column in Up Flow
Mode

[0168] To evaluate the difference between a down flow and an up flow
column system, a single test was carried out whereby the Aromatic 150 was
fed through the bitumen containing material in an up flow mode.

[0169] The column used for the bitumen extraction process was a 6''
internal diameter by 6' tall Schedule 10 steel pipe. The column included
flanges at the top and bottom of the column. The flange on the bottom of
the pipe had a 1/2'' port which was used for solvent inlet and outlet.
The bottom flange was covered with a 120 mesh screen. The top flange had
three 1/2'' ports which were used for the wash solvent inlet, nitrogen
inlet, and pressure relief valve.

[0170] 10 kg of clean sand was placed in the column on top of a 120 mesh
screen. 30 kg of ore with a bitumen content of 12.5% was placed in the
column on top of the clean sand. Aromatic 150 was introduced to the
column through the inlet on the bottom flange in an up flow mode at a
rate of 0.67 liters per minute. This amounted to a 4:1 Aromatic 150 to
bitumen ratio by volume. Nitrogen at a pressure of 20 psig was added to
the top of the column until dissolved bitumen in Aromatic 150 was driven
out of the column. The dissolved bitumen in Aromatic 150 was collected
and then pumped back into the column again through the bottom inlet at a
rate of 0.67 liters per minute. This process was repeated three times.
After a nitrogen displacement, methanol at a 2:1 methanol to bitumen
ratio by mass was introduced to the column through the inlet in the top
flange at a rate of 1.33 liters per minute. 20 psig of nitrogen was again
added to the top of the column to drive out any remaining dissolved
bitumen in Aromatic 150 as well as the methanol. The residual dissolved
bitumen plus Aromatic 150 phase was displaced with methanol and this
combined residual bitumen-Aromatic 150-methanol mixture was pumped back
into the top of the column at a rate of 1.33 liters per minute. After
washing completion, the residual bitumen-Aromatic 150-methanol mixture
was again driven out with 20 psig of nitrogen. This methanol washing
procedure was repeated once. After a nitrogen displacement, room
temperature water at a 3:1 water to bitumen ratio by volume was
introduced to the column through the inlet in the top flange at a rate of
3 liters per minute. A final nitrogen displacement at 20 psig was used to
drive out the water and residual methanol. The tailings were analyzed for
bitumen and assayed 1.27% bitumen. The residual methanol content of the
tailings were analyzed and determined to be 85 ppm.

Semi-Continuous Countercurrent Washing Using a Vertical Column Using
Different Wash Water Temperatures

[0172] The procedure outlined in Example was performed twice, with the
exception of using a down flow mode and the use of water having a
temperature below (45° C.) and above (75° C.) the boiling
point of methanol (65° C.) for the water wash step, as opposed to
the use of water at room temperature.

[0173] A complete mass balance for the 45° C. water trial is shown
in Table 6.

[0176] The methanol content of the final washed tails assayed 396 ppm
MeOH.

[0177] Comparison of the final tails methanol assays for the two trials
demonstrated that low levels of final solvent in the tails can be
produced.

Example 6

[0178] The effect of the presence of water in an aromatic solvent-polar
solvent system was investigated. Aromatic 150 was selected as the
aromatic organic phase and methanol was selected as the polar solvent.
Five aliquots of 250 cc total organic liquid were prepared each
containing different volume percentages of Aromatic 150 and methanol.

[0179] When the two organic phases were initially mixed, all five sample
phases were totally miscible and no separation of phases occurred. Then
water was added to each sample and the required volume of water needed to
produce an immiscible system was measured. It should be noted that the
water phase completely dissolved into the methanol phase. Hence only two
phases were noticed. This experiment confirmed that water acts as an
antisolvent or a "salting out" agent for a mixed aromatic-polar solvent
system.

[0180] One test was carried out using a light distillate that was derived
from a hydrocarbon cracking process as defined in U.S. patent application
Ser. No. 12/509,298. Since methanol has a lower density (˜0.8 g/cc)
then Aromatic 150 (˜0.9 g/cc), the methanol will separate as the
top layer and the Aromatic 150 will settle down as the bottom layer.

[0181] Two other findings were made. Firstly, if more than the minimum
amount of water necessary to separate the aromatic-polar solvent system
is added, the density of the methanol/water phase increases until it
ultimately reaches a density that is higher than the Aromatic 150 phase.
As a result, an inversion takes place. Secondly, the test, procedures
also demonstrated that if any Aromatic 150-methanol miscible mixture that
was left standing for enough time and exposed to the air, the mixture
became unstable due to the absorption of moisture from the air. Brownian
movements of separated phases in the miscible phase were clearly visible.

[0182] First solvent-wet tailings that have undergone bitumen-enriched
solvent phase separation through the addition of first solvent may
include about 12% first solvent (e.g., Aromatic 150, which may include
minor amounts of bitumen dissolved therein). The volume ratio of first
solvent to, polar solvent used to wash first solvent-wet tailings of
first solvent can range from about 1 to as much as 4. Every kg of tar
sand wills produce a first solvent-wet tailings containing about 120
grams of first solvent. Therefore, the amount of polar solvent used for
each kg of tar sand ranges 120 to 480 ccs of polar solvent. Athabasca tar
sands have a moisture content ranging from about 2 to 10 wt-%. Hence for
every kg of tar sands added to the process, there will be between 20 and
100 grams of water. To produce immiscible phases of first solvent and
polar solvent, one requires at least 8 vol-% of water in methanol as
shown in the Table above. This translates into 9.6 to 38.4 grams of water
per kg of tar sand. This range should be compared to the water content
originally present in tar sands (ranging from 20 to 100 gram per kg tar
sand). Thus, on average the tar sand itself should provide most of the
water necessary to facilitate the phase disengagement between the first
solvent and the polar solvent.

[0183] The above conditions were calculated for the overall process
configuration, but it should be realized that the initial flow of polar
solvent will not have access to the full amount of available water that
should be present in the first solvent-wet tailings. Consequently, as the
polar solvent is contacted with the first solvent wet tailings, there
will be a gradual increase in the water to polar solvent ratio and there
will therefore be a change in the miscibility as the polar solvent
travels through the first solvent wet tailings. Thus, the process can be
manipulated to create single or distinct phases where desirable through
manipulation of the water content. It should be further noted that this
phenomenon of salting out two miscible organic phases by water addition
is not limited to Aromatic 150 and methanol. When Aromatic 150 was
replaced by a light distillate (as shown in above table) the same
phenomenon was observed, albeit at an increased amount of water needed.
Similar phenomenon were seen where alternative alcohols (e.g., ethanol,
butanol, propanol) were used in place of methanol.

[0184] 200 kg of mined oil sands having 11.5 wt % bitumen content was
mixed in a drum with 32.5 kg of disbit. The mixed product was allowed to
settle and the excess liquid decanted off and the remaining solids placed
in a vertical cylindrical column having a height of 8 feet and a diameter
of 12 inches. A mass of 25.7 kg of Aromatic 100 was added to the top of
the vertical column on top of the solids and the top of the vertical
column was then sealed and a nitrogen inert gas purge was conducted to
drive trapped first solvent down and out of the vertical column. 60 psig
of inert gas was introduced into the top of the vertical column, and the
material driven out of the bottom of the column by the gas purge
contained 29 kg first solvent and 25 kg bitumen.

[0185] 43 kg of pentane was added to the top of the vertical column and
allowed to flow down through the interstitial pores in the material
loaded in the vertical column. The top of the vertical column was then
sealed and a nitrogen purge was conducted to drive trapped first solvent
down and out of the vertical column. 60 psig of inert gas was introduced
into the top of the vertical column, and the material driven out of the
bottom of the column by the gas purge contained 6 kg first solvent, 30 kg
second solvent, and 4 kg bitumen.

[0186] 54 kg of water was added to the top of the vertical column and
allowed to flow down through the interstitial pores in the material
loaded in the vertical column. The top of the vertical column was then
sealed and a nitrogen purge was conducted to drive trapped first solvent
down and out of the vertical column. 60 psig of inert gas was introduced
into the top of the vertical column, and the material driven out of the
bottom of the column by the gas purge contained 0.1 kg first solvent, 31
kg second solvent, 20 kg water and 0.1 kg bitumen. The remaining portion
of the water remained in the material loaded in the vertical column.

[0187] The material loaded in the vertical column was discharged from the
bottom of the vertical column. The majority of the material was inert
solid material, such as sand and clay. The material also included 250 ppm
first solvent, 450 ppm second solvent, 36 kg water, and 0.2 kg bitumen.

Example 8

Bitumen Extraction Process Using Paraffinic Solvent and Hydrocyclones

[0188] A slurry of oil sands and solvent is prepared. The slurry is
prepared by mixing 22.5 t/hr of mined oil sands containing 11.5% bitumen
with 2.7 t/hr of Aromatic 150. The slurry is introduced into a KREBS
D6BGMAX hydrocyclone of 6'' diameter and the hydrocyclone operates to
separate the slurry into a first disbit stream that leaves the
hydrocyclone from the overflow and a tailings stream that leaves the
hydrocylone from the underflow. The disbit overflow leaving the
hydrocyclone includes a mixture of first solvent and bitumen with some
solids. The overflow mixture includes 53.2% first solvent and 20.8%
bitumen and 26% solids. The underflow leaving the hydrocylone includes
inert solid material, such as sand and clay, bitumen, and first solvent.
The underflow mixture includes 70% inert material, 18% first solvent, 5%
water and 7.0% bitumen.

[0189] The underflow mixture is mixed with pentane to create a second
slurry. 11.9 t/hr of pentane is mixed with the underflow mixture to form
the second slurry. The second slurry is introduced into a KREBS D6BGMAX
hydrocyclone of 6'' diameter and the hydrocyclone operates to separate
the slurry into a first disbit stream that leaves the hydrocyclone from
the overflow and a tailings stream that leaves the hydrocylone from the
underflow. The overflow leaving the hydrocyclone includes a mixture of
first solvent, second solvent, and bitumen. The overflow mixture is
produced at a rate of 11.7 t/hr and includes 29% Aromatic 150 and 71%
pentane. The underflow leaving the hydrocyclone includes inert solid
material, bitumen, first solvent, and second solvent. The underflow
mixture includes 72% inert material, 1% first solvent, 20% second
solvent, 5% water and 0.7% bitumen.

[0190] The underflow mixture is mixed with water to create a third slurry.
12 t/hr of water is mixed with the underflow to form the third slurry.
The third slurry is introduced into a KREBS D6BGMAX hydrocyclone of 6''
diameter and the hydrocyclone operates to separate the slurry into a
first disbit stream that leaves the hydrocyclone from the overflow and a
tailings stream that leaves the hydrocylone from the underflow. The
overflow leaving the hydrocyclone includes a mixture of first solvent,
second solvent, water, and bitumen. The overflow mixture includes 2%
first solvent, 37% second solvent, 60% water, and 0.4% bitumen. The
underflow leaving the hydrocyclone includes inert solid material,
bitumen, first solvent, second solvent, and water. The underflow mixture
includes 70% inert material, 0.4% first solvent, 1% second solvent, 28%
water, and 0.4% bitumen. Alternatively the water wash portion can be
carried out in a vertical column as described in the water wash portion
of Example 7.

[0191] In view of the many possible embodiments to which the principles of
the disclosed invention may be applied, it should be recognized that the
illustrated embodiments are only preferred examples of the invention and
should not be taken as limiting the scope of the invention. Rather, the
scope of the invention is defined by the following claims. We therefore
claim as our invention all that comes within the scope and spirit of
these claims.